History Main / WithGreatPowerComesGreatInsanity

* ''Machinima/RedVsBlue'':

[[caption-width-right:350:My head is a cloud, your argument is invalid!]]

A.K.A. Comes Great Insanity for short. To go with the original version, ComesGreatResponsibility. Compare TheCorruption, AlmightyIdiot, DrunkWithPower, PowerHigh, GodForADay, MadGod.

[[caption-width-right:350:My head is a cloud, sanity is irrelevant.]]

A.K.A. Comes Great Insanity for short. To go with the original version, ComesGreatResponsibility. Compare TheCorruption, AlmightyIdiot, DrunkWithPower, GodForADay, MadGod.

[[quoteright:350:[[TabletopGame/MagicTheGathering https://static.tvtropes.org/pmwiki/pub/images/rsz_zur.png]]
[[caption-width-right:350:My head is a cloud, sanity is irrelevant.]]]]

[[quoteright:350:[[TabletopGame/MagicTheGathering https://static.tvtropes.org/pmwiki/pub/images/rsz_zur.png]]]]

* Unsurprisingly for such a {{Troperiffic}} series, ''Literature/WhateleyUniverse'' has a number of described -- and sometimes treatable -- psychological conditions that can result from possessing superpowers. Aside from [[ScienceRelatedMemeticDisorder Deidrick's Syndrome]] (which can affect almost any mutant, but is most common among Devisors and electrical Manifestors), there are [[ComicBook/HarleyQuinn Quinzel]]-[[ComicBook/NormanOsborn Osborn]] Syndrome, which makes the sufferer DrunkOnTheDarkSide; Hercules Syndrome, which causes Exemplars -- '''all''' Exemplars -- to have difficulty controlling their emotions; and Galahad Syndrome, which causes monomania (often of the ChronicVillainy or ChronicHeroSyndrome varieties), again being a more or less universal tendency in Exemplars. Part of the justification used by the [[FantasticRacism hate groups]] Humanity First! and the Knights of Purity is their claim that mutants invariably go off the deep end, making even those with harmless powers too dangerous to allow in society.

It seems like any major military- or corporate-backed venture to give a [[{{Muggles}} mundane person]] [[StockSuperPowers super powers]] or just enhance their [[BadassNormal normal abilities]] results in the test subject going [[PsychoPrototype uncontrollably berserk]] as a [[GoneHorriblyWrong side-effect]].

[[caption-width-right:350:[[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=121162 Zur the Enchanter]] does it in style.]]

[[caption-width-right:350:[[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=121162 Zur the Enchanter ]]does it in style]]

{{Invisib|leJerkAss}}ility seems to drive one insane (because when you're out of your sight, you're out of your mind), or at least evil, more than any other power, because it lets you [[PowerPerversionPotential spy on people undetected]] and [[{{GIFT}} escape easily without consequences]]. Creator/HGWells' novel ''Literature/TheInvisibleMan'' is the TropeCodifier for invisibility letting you be evil in the modern era, but the germ of the story is [[OlderThanFeudalism much older than that]]; if you asked Wells where he got the idea he would probably have mentioned Creator/{{Plato}}'s tale of the ring of Gyges (from ''Literature/TheRepublic'').

[[caption-width-right:350:[[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=121162 Zur the Enchanter does it in style.]]]]

* WithGreatPowerComesGreatInsanity/{{Fanfiction}}

** The Meta has the abilities and A.I. of every Freelancer it has killed so far. That many A.I. in one body, however, have caused it to be more than slightly snarling mad. To the point where it doesn't seem able to speak itself, only growl. ([[DeadpanSnarker Church]] was naturally ''thrilled'' when he heard this.)
--->'''Church:''' Oh great, powerful, and crazy. What a winning combo.

--->'''Grif:''' Simmons, I think you've gone mad with imaginary power.\\
'''Simmons:''' Oh no, Grif. I've gone mad with very real power.

* Burnscar from ''{{Literature/Worm}}'' becomes more unstable and violent the more she uses her [[PlayingWithFire power]].
** A lot of characters in ''Worm'' fit this trope. Since superpowers can only be gained by going through [[TraumaticSuperpowerAwakening highly traumatic experiences]], most parahumans aren't particularly stable individuals.
** Skitter's trigger event caused her to abruptly gain awareness of millions of insects. The shock of this was so severe it was assumed she'd had a psychotic break and she spent a week in a psych ward. [[spoiler:After having Panacea mess with her brain, she gains the ability to control people but her mind is gradually taken over by her shard.]]

[[quoteright:331:[[TabletopGame/MagicTheGathering https://static.tvtropes.org/pmwiki/pub/images/ZurTheEnchanter_1159.jpg]]]]
[[caption-width-right:331:[[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=121162 Zur the Enchanter does it in style.]]]]

!!Examples:

[[folder:Western Animation]]
* ''WesternAnimation/SupermanTheAnimatedSeries'': Luthortech has two examples of experimentation causing insanity.
** ComicBook/LexLuthor creates a super suit ostensibly to help the police fight crime. The officer testing it builds an unhealthy bond with it and becomes drunk with power, forcing the Man of Steel and John Henry Irons to take him down. Irons later worked out the flaws in the suit that caused this behavior and created his iconic "ComicBook/{{Steel}}" armor. Interestingly, the first opponent he fights as Steel is Metallo, the below example.
** Luthor poisons unwitting gangster John Corben, then offers to save his life with the Metallo project. Corben, advised only that there may be "some adjustments needed" to help him live a normal life after the process, accepts. But in his new robot body, the hedonistic Corben can't feel, smell, touch, or taste anything, and becomes destructive in his rage at his human sensations being lost. To be fair, Corben was already a criminal and card carrying psychopath.
* In ''WesternAnimation/Ben10UltimateAlien'', this is revealed to be the reason behind Kevin's villainy in the first show. Absorbing energy causes insanity in people with his powers: before he'd even met Ben, he was hooked on electricity and was planning to do things like crash trains full of people together to make a buck. After accidentally absorbing energy from Ben's Omnitrix, he ''really'' goes nuts, and turns into a full on PsychoForHire. After the TimeSkip in ''Alien Force'' and ''Ultimate Alien'', he is noticeably wary about doing it.
** Aggregor claims that this is BS. However, since he is already an insane [=supervillain=], he probably isn't the most reliable source.
** Kevin ends up proving it by absorbing Omnitrix energy to stop Aggregor, but loses his sanity and takes the power Aggregor stole in the process. He then proceeds to try to drain energy from anyone with power, right after giving out DisproportionateRetribution to anyone he's had problems with. He is barely stopped long enough to cure him.
** This is also a problem with the Alpha Rune, the mystical artifact from which all magic flows. Whomever wields it is gradually driven to madness, as shown by both [[EvilOverlord Adwaita]] and [[DarkMagicalGirl Charmcaster]].
* ''WesternAnimation/DannyPhantom'':
** Dark Danny, though the whole thing about watching helplessly as your family and friends get blown up and getting your super-powered ghost half removed did give a good start... but he only started a murderous rampage ''after'' getting his enemy's power. His [[FutureMeScaresMe past self]] is extremely horrified.
** Vlad, as he seemed to be largely content with his life before the accident. Except that his one true love went and married their idiot friend who Vlad thinks caused the accident anyhow.
* ''WesternAnimation/TeenTitans'':
** ComicBook/{{Raven}} must suppress her anger, otherwise she takes on a far more evil side that has no mercy and takes up a form that can border on EldritchAbomination.
** WordOfGod ascribes this trope to the Amazing Mumbo; originally a harmless stage magician, when he got ahold of a magican's wand that was actually magical, it granted him [[MagiciansAreWizards full-fledged sorcerous powers]], turning him into a RealityWarper of such power he's even a DomainHolder, with a pocket-plane of which he is the DimensionLord tucked away inside of his top hat. However, the powers also drove him completely ''bonkers'', and as such he now uses them to create "real" magician tricks that he uses for petty crimes like robbing banks.
* In ''WesternAnimation/TheBatman'', when good cop [[FaceHeelTurn Ethan Bennet becomes Clayface]], he goes on a murderous vendetta against his former Captain. It's later asserted that the incident that turned him into Clayface damaged his mind, and that, the more he keeps his form, the less unstable he will be. In fact, whenever he stays in his normal form, he's polite and rational, but the moment he uses his powers, he tends to become violent and unhinged.
* In ''WesternAnimation/AvatarTheLastAirbender'', Aang can enter the Avatar State, channeling the power of all his previous incarnations. You'd think channeling all those former Avatars would make him calm, wise, and experienced, but no... Instead he gets all [[GlowingEyesOfDoom incandescent]] and frags everything in sight. However, true mastery of the Avatar State includes being able to control it, [[spoiler:which he finally manages to achieve in the GrandFinale]].
** In the GrandFinale, after being made Fire Lord, [[spoiler:Azula]] ''loses it''. In an inversion, it's because [[spoiler:she's ''losing'' power and she knows it -- her friends had shown themselves insufficiently scared of her and defied her, and her dad appointed her Fire Lord right before turning the position into "irrelevant figurehead". Paranoia of further betrayals if she didn't instill fear in everyone around her, and insecurity that no one (especially her [[MissingMom mother]]) truly loved her for who she was, caused her to finally snap.]]
* In ''WesternAnimation/TheSpectacularSpiderMan,'' three [=supervillains=] qualify when they get bonus mental instability with their powers. Electro and ComicBook/DoctorOctopus each suffer a FreakLabAccident. Electro gets [[PowerIncontinence volatile]] [[PsychoElectro electricity]]-based powers, then [[FreakOut freaks out]] at his loss of humanity. Comicbook/DoctorOctopus' [[ArtificialLimbs robotic arms]] are [[{{Cyborg}} fused]] [[UnusualUserInterface to his spine]] when radiation fuses his mechanical arms with his spinal column, which causes an [[NotSoHarmlessVillain extreme]] [[MadScientist personality change]]. The Green Goblin ''claims'' that he suffered no blackouts and no change in personality from his PsychoSerum, but it is very likely that he is in denial considering that he actually keeps acting crazy and speaking in rhymes while he's hovering above the prison in season 2 while no one can hear him. The Goblin formula probably enhanced his insanity, however.
** John Jameson was infected by alien spores, which made him super massive, super strong, and essentially a FlyingBrick without the flying, but, over time, messed with his head, making him filled with rage and aggression. After Venom threw him into a rage (making him think the one messing with him was Spider-Man), Spidey was able to purge the spores from his system, making his body return to normal, but he was severely addicted to the power, and had to be admitted to an insane asylum. The effect was made more evident due to John having a cell right next to the now completely insane Electro, who babbles on about how [[ThatManIsDead he has no more human identity]].
*** Eddie Brock would also qualify as an example. When he's stripped of the symbiote in a battle at Peter's high school, he is strapped to a stretcher and removed by two hospital orderlies, screaming at a crowd of spectators that "WE'RE VENOM!" (though he had problems beforehand and the symbiote just released the inhibitions).
* ''WesternAnimation/SwatKats'':
** Dr. Viper was formally one of two biochemists who invented the Viper mutagen, which was intended to regenerate plants. Then he decided to try and steal it so he could sell it, directly leading to his transformation into the crazed, lizard-like Dr. Viper.
** The otherwise peaceful Dr. Greenbox invented Zed, a robot that could repair any mechanical device. When said robot went on a rampage, he initially came along to help stop it...but was so delighted with how powerful his creation was that he tried to sabotage the mission and ended up merging himself with Zed.
* An episode of ''WesternAnimation/SamuraiJack'' centers around Jack defeating three shadowy warriors with amazing powers who attack anyone who comes near. After the battle, it turns out that the warriors were actually three men who used a magic well to wish for the power to be the greatest warriors in the land. While the well granted their wish, it also made them blind and took their free wills. And it was Aku behind this.
* Maria from ''WesternAnimation/ElTigre'' is a mild mannered family woman who is terrified of danger and hyperventilates when it is around her or her family. However, when she puts on her magical glove, she transforms into the 'superheroine' Plata Peligrosa. If she only has it on for an hour, she is fine, but a second longer and she becomes crazed and will do anything for a fight (even free crooks from jail). At one point, she even starts attacking herself (because she has released villains and that is evil) and trying to kill HER OWN SON because he is trying to help her when she has labeled herself evil and attacking herself.
** Arguably Manny himself and the El Tigre beforehand. Those who end up with the title of El Tigre along with the belt buckle end up suffering from whether to become good or evil, with the first El Tigre having gone quite mad. However, they also have more raw power and abilities than either the Good or Evil family members. Besides the enhanced capabilities along with chain claw, the first El Tigre explains that Manny will keep getting new powers after demonstrating some such as growing the claws to be quite long and a sonic explosion-causing roar. Lastly, El Tigre has the power to ''escape the underworld'' with the power of the ''Ancient Tiger Spirit.''
* This is the hat of pretty much ever version of Galvatron that's ever appeared in any iteration of ''WesternAnimation/TheTransformers''. He's usually a powered-up version of Megatron, and he's also usually [[AxCrazy batshit insane]]. The one exception to this is IDW's run of the comic books, where the two are separate characters rather than Galvatron being a stronger upgrade of Megatron, though that Galvatron is possibly even more evil to make up for it ([[DarkerAndEdgier certainly he's allowed to do]] much more evil things than most other versions could get away with).
* Two examples from ''WesternAnimation/BeastWars'':
** Rampage. A Maximal experiment to create an immortal spark, he is nigh-immortal but also [[AxCrazy completely insane]] and takes great pleasure from torturing others in the sickest ways possible. He's also a [[ImAHumanitarian cannibal]].
** [[spoiler:Megatron]] too. Once he [[spoiler:mingles his spark with that of his namesake, and then takes control of the Nemesis]], he goes ''completely'' bonkers and begins [[AGodAmI quoting the Transformer bible]].
** Optimus Primal had a couple of instances too. When he carried the spark of Optimus Prime, he not only got a new body out of the deal, but took on some of Prime's mannerisms. Prime was an incredibly ''good'' character, so Primal didn't get the nasty side effects Megatron got. In another episode, he gets injected with a serum that was [[GoneHorriblyWrong supposed]] to turn him into a coward. However, it instead ''removed'' all fear, turning him into an unstoppable berserker. He didn't get stronger, just ''fully'' utilized his already considerable strength.
* In ''WesternAnimation/TransformersAnimated'', [[WordOfGod Word of God]] says that the experiment that turned Blitzwing into a triple changer drove him [[SplitPersonality insane]].
* Ratchet on ''WesternAnimation/TransformersPrime'' goes nuts when hopped up on synthetic Energon.
** [[spoiler: Silas gets hit with this as well when he gets drugged up on ''several'' doses of the stuff courtesy of Knock Out as payback for hollowing out Breakdown's corpse and turning it into a mech suit. [[FromBadToWorse And then he and Starscream get the]] [[SarcasmMode brilliant]] [[OurVampiresAreDifferent idea to throw in some]] [[MadeOfEvil Dark Energon...]]]]
* in ''WebAnimation/TheTransformersCombinerWars'' Starscream goes completely insane soon after using the Enigma of Combination, and he goes out of control, attacking everything.
* [[InsistentTerminology Professor Von Madman]] in the ''WesternAnimation/BuzzLightyearOfStarCommand'' episode "Eye of the Tempest" after he tested his revolutionary crystal/human hybrid technology [[ProfessorGuineaPig on himself]]. But he has [[MadScientistsBeautifulDaughter a daughter]]...
* In ''WesternAnimation/StaticShock'', the Big Bang was occasionally thought to invoke this in earlier episodes. Notably, it's why [[SecretKeeper Richie]] refused to trust Static when the metahuman Replay was framing him, believing that Static just took longer to go nuts than the others. However, since the Big Bang took place in the middle of a gang war, the guys who got the highest doses were generally not great people to begin with, and later episodes introduce other perfectly sane superpowered characters.
* Inverted and then played straight in ''WesternAnimation/ReBoot''. Hexadecimal started out very powerful and insane. When she gets reformatted into a sprite and as a result is depowered, she becomes very sane and cheerful. But then she needs to go viral again to fight Daemon, and the powerup makes her insane again.
* ''WesternAnimation/AdventureTime'':
** Simon Petrikov, aka [[WasOnceAMan the Ice King]]. An antique merchant from JustBeforeTheEnd who found an ArtifactOfDoom that gave him immense magical power and immortality... but also slowly drove him to become a demented, miserable [[TheSociopath sociopath]] who only has the vaguest memories and a FreudianExcuse from his past life.
*** In the season 5 two-part opener, [[spoiler:Farmworld Finn]] wears the crown and starts going insane too, complete with maniacal laughter.
*** The crown has been driving people insane since it was first created, according to the episode "Evergreen". [[spoiler: The first person to wear it, Urgence Evergreen's apprentice Gunther, wished to be more like his master... [[BeCarefulWhatYouWishFor but he turned into]] ''how he deep-down perceived'' Evergreen, which was a bearded bully who goes around blasting things with ice and shouting [[MadnessMantra "Gunther, no!"]]]]
*** In the season 6 episode "You Forgot Your Floaties" it is revealed that this may be the case with all magic, through the triumvirate of "Magic, Madness, and Sadness." [[spoiler: Betty goes crazy after accidentally absorbing Magic Man's powers.]]
** Subverted, however, by Flame Princess in "Vault of Bones". As she is attacking the monsters with her flames, she shifts into OneWingedAngel form, laughs maniacally, and generally seems to be going this way... but then, when one of them grabs Finn, [[spoiler:she opts to intimidate it into letting him go, rather than risk hurting him by burning it, and she seems perfectly normal later]].
** This is a common problem in single-episode plots, as well. As Jake says in "Crystals Have Power", after Tree Trunks has come down from a temporary-power-induced bout of deranged violence:
--->'''Jake''': If I had a penny for every time someone went crazy-hopped-up on magical energy, I'd be Abraham Lincoln!
** {{Inverted|Trope}} in "[[Recap/AdventureTimeS6E4TheTower The Tower]]," when Finn's trauma over losing his arm and being [[DisappearedDad abandoned by his father a second time]] unlocks his latent psychic potential, creating a powerful psionic ghost arm. [[InvertedTrope With Great Insanity Comes Great Power]].
** "The Real You" had Finn don a pair of [[SmartPeopleWearGlasses magical glasses]] that make him TheOmniscient. By the end of the episode he's done a science experiment that threatens to kill them all, and is cackling cheerfully about the whole thing until [[EmperorScientist Princess Bubblegum]] snaps him out of it. [[spoiler:Amusingly, we then learn that the glasses let him ''know'' that he was going to go insane, so PB's help was part of his BatmanGambit.]]
** In the miniseries ''Elements'': [[spoiler:Patience St. Pim creates a spell to wake the Elementals powers forcibly, this leads to them being overturned by their own elements and parting the land of Ooo in 4 parts, one for each. Fire Princess turns into a dragon that looks for things to fight against, as well as all her followers, Bubblegum becomes a always happy Tower-sized entity that turns everyone around her in candy overly sweet versions of themselves and does BrainwashingForTheGreaterGood, Slime Princess becomes tyrannical, lazy and wishes to absorb other slimes into her own besides behaving and talking in a similar fashion to [[Franchise/StarWars Jabba The Hut]], and Patience herself becomes gloomy and melancholic]].
* ''WesternAnimation/{{Freakazoid}}'' is the rare heroic example. Becoming the titular hero drives Dexter insane, but in the sense of "[[{{Cloudcuckoolander}} five year old manchild]] [[FunPersonified on a sugar high]]" level of insane instead of "[[SuperpoweredEvilSide Mwahahahaha! Ultimate power to rule the world!]]" level of insane.
* Spider-Carnage of ''WesternAnimation/SpiderManTheAnimatedSeries'' is an example of this happening to a [[EvilTwin version]] of Spider-Man himself.
* The [=EVOs=] of ''WesternAnimation/GeneratorRex'' can get hit with this, BodyHorror, or ''both''. The clearest example would probably be Breach, though she's at least ''coherent''. No-Face from the Bug Jar also demonstrates a seriously degraded mental state, though not in the same way as Breach. And some [=EVOS=] are so far gone, it's easy to forget they were [[WasOnceAMan ever human in the first place]].
* Nerissa of ''WesternAnimation/{{WITCH}}'' is a sad example of this. She was actually pretty well-adjusted until she gained control of the Heart of Candracar. The Oracle tried to cut her off at the pass, making her hand it over to her best friend, Cassidy. All it did was drive Nerissa farther into needing it, in which she killed her friend in cold blood. A good generation later, she comes back, pulling off a plan to obtain more Hearts "for the greater good of the universe".
* Happened to Goofy in the ''WesternAnimation/HouseOfMouse'' short "Sandwich Makers".
-->'''Donald:''' He's ''lost'' it.
* In a less malevolent example, an episode of ''WesternAnimation/AladdinTheSeries'' had Genie's powers be transferred to Iago. Iago notices pretty quickly that, along with Genie's powers, he has also become more eccentric and strange, while the de-powered Genie becomes more morose. Apparently, possessing semi-phenomenal, nearly-cosmic power makes you a {{Cloudcuckoolander}}.
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'':
** In "[[Recap/MyLittlePonyFriendshipIsMagicS3E5MagicDuel Magic Duel]]", [[RivalTurnedEvil Trixie]]'s sanity deteriorates while under the influence of a magic-boosting ArtifactOfDoom; the first thing she does after banishing Twilight being to turn Ponyville into a micronation with her as its [[TheCaligula Caligula]], then it comes to a head when she has [[ThoseTwoGuys Snips and Snails]] drag her chariot across the ground, as [[AbsurdPhobia she is now so paranoid that she can't trust wheels]].
** In "[[Recap/MyLittlePonyFriendshipIsMagicS4E23InspirationManifestation Inspiration Manifestation]]", the more Rarity uses the book's power, the more deranged she becomes.
** In "[[Recap/MyLittlePonyFriendshipIsMagicS9E25TheEndingOfTheEndPart2 The Ending of the End – Part 2]]", Pinkie Pie briefly absorbs Discord's chaos magic and goes mad with her newfound power. Fortunately, Discord promptly drains his magic back out of her.
--->'''Pinkie Pie:''' ''I COULD TRANSFORM THE COSMOS SO EVERYTHING IS MADE OF ICING!''
* In the ''WesternAnimation/XMen'' animated series, Apocalypse was this according to Professor Xavier, which means that unlike Magneto and the group behind the Sentinels, he cannot be reasoned with and has to be stopped at once by the X-Men before he will destroy the world.
* In the ''WesternAnimation/BatmanBeyond'' episode "Heroes", three scientists are transformed by a FreakLabAccident. They are angry and frustrated at being unable to lead normal lives, and are pushed over the edge when they learn that the transformation is killing them and driving them insane -- and that the "accident" was deliberately set up by a colleague who had intended to [[MurderTheHypotenuse kill his romantic rival]].
* Sugilite from ''WesternAnimation/StevenUniverse''. A building sized fusion of Garnet and Amethyst, she's a walking wrecking machine. Problem is, the combo of Amethyst's wild personality and Garnet's power makes her violent and hard to manage. If the fusion lasts too long, she becomes a serious threat.
** It's implied that all fusions can have that effect, especially forced fusions. [[spoiler: Malachite]] is essentially a case of multiple personality disorder (including with Steven having a short view on the two gems inside who are both [[DrivenToMadness going insane from the abuse they put each other through]]) and [[spoiler: the Cluster]] is this [[FromBadToWorse times hundred]], even adding AndIMustScream and BodyHorror to the mixture.
* In the ''WesternAnimation/AtomicPuppet'' episode "Sword Sisters", Pauline becomes the superheroine Sword Sister after she gets her hands on a CoolSword, but soon goes mad due to its incredible power. Joey and AP are forced to find the sword's original owner in order to stop their friend.
* Dark magic has this effect in ''WesternAnimation/WinxClub'': as it's fueled by negative emotions, the more powerful its users become, the more they risk becoming fully evil.
** Best shown by the Trix:
*** They start out as powerful, ambitious and mean, but not particularly evil (especially [[TokenGoodTeammate Darcy]], who actually fell in love and got together with Riven halfway through the first season);
*** The moment they got their hands on the enormous power of the Dragon's Flame (a power-up they couldn't handle), they ''instantly'' became borderline {{Omnicidal Maniac}}s bent to take over the universe or destroy it trying (with Darcy 'breaking up' with Riven in a nightmarish BreakTheHaughty sequence, in which she claimed she was only using him);
*** At the start of season 2 they've lost the Dragon's Flame, and aside from the mental trauma from getting imprisoned at [[TastesLikeDiabetes Lightrock]] (a FateWorseThanDeath, according to them), they seem back to normal;
*** Soon after Darkar give them the Gloomix power-up, and they grow more sadistic;
*** In season 3, without the Gloomix and with ''little'' negative emotions due to their crush on Valtor, they're at their weakest, only returning to be dangerous when facing Bloom (who they blame for defeating them and letting them get imprisoned at Lightrock);
*** In the second movie and early season 5, after the Ancestral Witches' tutelage brought them on par with Believix fairies, they're back to Gloomix-like evil;
*** When they get the Dark Sirenix (and somehow maintain that level of power even after losing it), they're back trying to take over the universe.
* In the episode "The Forgotten Element" of ''WesternAnimation/{{Ninjago}}'''s fourth season, Kai briefly becomes corrupted by the power of Master Chen's Staff of Elements and it causes his suppressed envy of [[TheChosenOne Lloyd]] becoming the Green Ninja to surface. Fortunately, it doesn't last long.
[[/folder]]

[[folder:Web Comics]]
* ''Webcomic/TheOrderOfTheStick'': When V has spoken the Four Words, he/she merges mentally with three of the most evil but powerful mages ever, and therefore it's justified his/her mental state is a little vague thereafter. [[spoiler:Then it's later revealed that the splice has as much effect on one's alignment as a cheerleader would on the final score of a game. The fiends just lied to him/her because nothing makes people do a horrible act on their own like having them believe that they're not responsible for their actions, especially when wielding great power.]] V was already pretty unhinged before the event. Transe deprivation does that to an elf.
* ''Webcomic/{{Narbonic}}'':
** The super-intelligent gerbils, with the exception of the original, Artie. It's explained that, unlike Artie, the other gerbils weren't genetically modified to handle super-intelligence, resulting in insanity. But when the sane super-intelligent hamsters show up, they're megalomaniacs too.
** Also, the mad geniuses in the comic [[ScienceRelatedMemeticDisorder are only geniuses]] ''[[ScienceRelatedMemeticDisorder because]]'' [[ScienceRelatedMemeticDisorder they're mad]]; if their madness were cured, they would be BroughtDownToNormal. In fact, the geniuses have to go past mad and out the other side... and then it's a crapshoot. Helen Narbonic reins in her crazy because of romantic feelings.
* Ian Samael of ''Webcomic/ErrantStory'' starts to fall into this trope after obtaining godlike powers. To his credit, it did take [[spoiler:his mother killing herself and his sister to finally drive him off the deep end]].
* ''Webcomic/GirlGenius'': The Sparks (or mad scientists) are often (although not always) insane. This is explained in the story as a side-effect of the Sparks' realization of their abilities (also known as the Breakthrough), which is usually traumatic to say the least. Some of the insanity seems to be inherent in the Spark itself; even the protagonist, the relatively sane and heroic Agatha [[spoiler:Heterodyne]], has shown utter singlemindedness and vengeful wrath while in the throes of a particularly Sparky moment.
* This is implied to be happening to Ysengrin from ''Webcomic/GunnerkriggCourt''. He received [[ShapeshifterWeapon weaponized]] [[ArtificialLimbs wooden arms]] and GreenThumb powers from Coyote; after seeing him use them, Jones declared that he is "drawing closer to the brink of insanity." [[spoiler:It certainly doesn't help that Coyote erases his memories whenever he begins to have a crisis of conscience, either.]]
** And also [[spoiler:Jack after being sucked into Zimmingham]], who's gained always-on ether-vision and the ability to fly while simultaneously losing a large chunk of sanity.
** Turns out he was possessed though, so it's [[PowersViaPossession something else entirely]] (although the whole "not eating or sleeping" thing probably wasn't doing anything for him).
* ''Webcomic/TheBMovieComic'': In the invisible killer arc, the process that makes a person invisible can also make them quite frightfully deranged, but only if the person has a basic character flaw to serve as a basis. The scientist then also uses the treatment on Snuka so they can fight the invisible killer, on the assumption that anyone working closely with the professor must be a person of impeccable character. Not quite...
* ''Webcomic/CwensQuest'': This seems to be case with the [[http://www.drunkduck.com/Cwens_Quest/index.php?p=467213 Witch Queen]]. She is easily the most magically inclined character in the series, and while normally smart, she seems incapable of mentioning the word magic without bursting into bouts of insane [[LaughingMad Maniacal Laughter]] that would scare most versions of the Joker. It is even clearer she is brilliant but insane in her Twitterings.
** Also, Cwen's father. We get to see his centuries-long metamorphosis in short bursts from a science nerd to a fashion-obsessed neglectful parent with a loose grip on reality, due to the power that his technology granted him.
* In Mark Shallow's current webcomic, ''Webcomic/AntiheroForHire'', Wizard is an example of this, despite being extremely intelligent. Waterfall, an adversary using the same technology, snaps with the same kind of insanity at the sight of her sisters being threatened, which invoked ''ItsPersonal''.
* In ''Webcomic/ElGoonishShive'', this is [[http://www.egscomics.com/?date=2010-06-30 revealed to be]] the reason why Immortals "reset" every two hundred years. As time goes by, they become "more bored, more powerful, and less sane," which as Jerry notes is "kind of a bad combo." This is why [[spoiler:Pandora]] acts the way she does, since alleviating boredom through certifiably insane plots is her entire reason for doing things. She stopped counting her age [[http://www.egscomics.com/egsnp.php?id=300 at 299]], which was a few centuries ago, and her immediately previous incarnation remembers [[spoiler:the last time magic changed its own rules, which was so long ago that the fact this even ''can'' happen was lost to time]].
* In ''Webcomic/{{Endstone}}'', rocking the Banestone will drive the rocker crazy.
* Dragos from ''Webcomic/TheBeastLegion'' falls into this trope perfectly & it's clearly seen in the dialogue on [[http://www.thebeastlegion.com/?p=222/ the final page of Issue 2]]. But he does have a great amount of power to back his claim.
* In ''Webcomic/MoonCrest24'', Drake accuses Aleck of this.
* ''Webcomic/EerieCuties'' arc "[[HappyFunBall Doom Panties]]". Chloe was always a shy nice girl, except when her friend shared a bottle and "her inhibitions just melted". When her {{succubus}} powers got boosted, she began to "[[PowerHigh feel awesome]]" and put up quite a show, quickly rolling to the "scary" side. No malice at all, but Chloe won't let anything stand in the way of her fancy -- and since she got an excess of power to begin with, for almost anyone else it's a cue to take cover.
* There are three varieties of this in ''Webcomic/{{Homestuck}}'':
** Grimdarkness, which Rose acquires when she [[GoMadFromTheRevelation Goes Mad From The Revelation]] of knowing the moral nature of [[EldritchAbomination The Noble Circle of Horrorterrors]]. In this state, she only speaks in Eldritch Language, wields the horrorterrors' cosmic power, and has only her inevitably doomed RoaringRampageOfRevenge against Bec Noir on her mind. She is cured of it only when Bec Noir kills her and John revives her dreamself.
** The Rage Aspect, especially in the hands of "destructive" classes. Both of the trolls to which Rage powers are bestowed are quite mild-mannered at first. Indeed, half the powers of Prince and Bard involve either the ''destruction'' of Rage or the ''invitation to destroy'' Rage. It's the other half of those powers, where Kurloz destroys with Rage and Gamzee invites destruction through Rage, that, with the right triggers, make both of them, along with their ancestral counterparts, the {{Monster Clown}}s that they are.
** And finally, Trickster Mode. Aesthetically, it looks like the [[TastesLikeDiabetes polar opposite]] of Rose's eldritch throes, but it makes a user [[GrotesqueCute just as insane]], if not more. While it's first engaged by Jane when she licks a [[GRatedDrug lollipop]] juju laced with a powerful PsychoSerum, it's also a contagious [[TheCorruption Corruption]]. It gives any player who engages it manic euphoria, making them [[StepfordSmiler appear insanely happy]] and giving them bright, candy-themed clothing, accessories, and even [[HeartIsAnAwesomePower powers]] that only barely mask the mental side-effects. The worst part? It spread from Jane to Jake, Roxy, and Dirk before finally wearing off.
* ''Webcomic/{{Crankrats}}'': So it turns out [[WeCanRebuildHim having your organs replaced]] by a series of [[AppliedPhlebotinum mechanical steampunk abominations]] tends to make you go mad with power. [[TooDumbToLive We couldn't possibly have seen that coming]].
* ''Webcomic/{{Blindsprings}}'' has the Gravers, Orphics that have their magic twisted by Academist sigils implanted in their bodies. Thanks to the opposite nature of the two types of magic in them, they're extremely powerful but extremely unstable at the same time, a bad combination for both those around them and themselves.
* ''Webcomic/{{Widdershins}}'': Although most wizards can keep a level head about their magic, the bounty hunter Harry Barber has seen her [[https://www.widdershinscomic.com/wdshn/december-14th-2011/ fair share]] of the ones who go off the deep end, so her perception of an ordinary wizard is a bit skewed.
--> '''Sidney:''' Surely you see lots of wizards in your line of work.\\
'''Harry:''' Not... ''normal'' ones. It's mostly the mad types, and they're less subtle. Y'know... fine for years, then suddenly it's "[=OoOOoh=] I will summon an anger spirit because my neighbours' dog did its doings in my garden". ''Nutters.''
* This turns out to be the main reason for Leena's drop into madness in ''Webcomic/LookingForGroup'' -- she was a descendant of the Archmage, and it turns out that the power contained is enough to seriously warp a brain. When Richard volunteers to take her power, she asks him, "Aren't you worried about going insane?" To which he replies, [[EvilSorcerer "Does water worry about getting wet?"]]
[[/folder]]

[[folder:Video Games]]
* Whenever anybody attempts to use the Orochi power in ''VideoGame/TheKingOfFighters'' series, it usually results in either death (Rugal Bernstein), insanity (Iori & Leona), or a [[AGodAmI God complex]] (Chris, Yashiro, and Shermie).
** Averted in regards to Sie Kensou: he possesses the Dragon Power, which has been set up to be an astronomical power source that could potentially put him above the franchise's most powerful characters, [[GameplayAndStorySegregation but doesn't really affect his in-game performance]]. Kensou himself justified this, explaining that he tries not to tap into the Dragon Power too much because, having been in ''KOF'' since the very beginning, [[GenreSavvy he's seen countless examples of people falling into this trope and has no desire to join them]].
* The Nameless One of ''VideoGame/PlanescapeTorment'' gained immortality, but at the cost of his memory, which he periodically loses. Each reincarnation develops its own brand new personality, which is often insane. One of them was ''awesomely'' so. Another, one of the most dangerous, was mostly sane, but had the little problem of being a complete sociopath.
* Kefka from ''VideoGame/FinalFantasyVI''. [[spoiler:And gaining godhood halfway through the game makes him worse.]] It's all but stated explicitly by a few {{N|onPlayerCharacter}}PCs in the game that the process that made him a {{Magitek}} knight before the game started turned him into [[AxCrazy a raving psychopath]] from the get-go. It was stated that he was [[PsychoPrototype the first test subject as well]].
* ''VideoGame/FinalFantasyVII'' has its own version; being injected with Jenova cells makes you powerful, but it also leaves you vulnerable to becoming BrainwashedAndCrazy -which is what happened to Sephiroth (though it only started when he learned the truth). And Cloud, until he overcomes them.
** Before Crisis plays the traditional version of it. After summoning Zirconaide, Fuhito's body is transformed as the as-of-yet incomplete summon expresses itself through him. He becomes incredibly powerful, but only retains a bit of whatever sanity he had left (he was kind of a Hojo Jr. already)
** Interestingly enough, the only person that ''doesn't'' go crazy from Jenova cells is Zack. [[VideoGame/CrisisCore And we all know how that ended]].
** Although it is never specified if the Jenova cells caused Hojo to be brainwashed, his injecting himself with Jenova's cells (with an amount that obviously was a much larger amount than that of a SOLDIER) certainly caused Hojo to become a ''lot'' more crazy.
* ''VideoGame/SinAndPunishment'' places Saki (as well as his son, Isa, in the game's sequel) as the victim of this trope once he becomes a half-Ruffian, as Achi tells Saki that the only thing that can redeem him at this rate is by [[ThePowerOfLove accepting his humanity by falling in love with]] ActionGirl Airan.
* ''Franchise/TheElderScrolls'':
** Throughout the series, this is common for any [[DeityOfHumanOrigin mortals who obtain great (or sometimes godly) power]]. One could argue that you have to be at least a little bit insane in the first place to seek such power, and obtaining it does these individuals no favors...
** ''[[VideoGame/TheElderScrollsIIIMorrowind Morrowind]]'':
*** In the {{backstory}} Dagoth Ur and the three members of the Tribunal all tapped into the divine power of the Heart of Lorkhan in order to become {{Physical God}}s. [[BigBad Dagoth Ur]] was much less restrained in his consumption of power from the Heart, making him much stronger than the Tribunal once he was able to resurrect, while also making him [[AxCrazy much more insane and dangerous]].
*** The [[OurGodsAreDifferent Daedric Prince]] Azura, who guides [[PlayerCharacter the Nerevarine]] in unbinding the Heart to cut off Dagoth Ur (and the Tribunal), states that mortal minds are not equipped to handle the rigors of godhood and that this would have been the fate of each member of the Tribunal eventually. Only [[spoiler:Almalexia]] shows full blown AxCrazy insanity in the game, specifically the ''Tribunal'' expansion of which she is the BigBad. However, based on what she says (and what others, mainly Azura and Vivec, say about her), she actually ''Inverts'' the trope. It's not the power that drove her mad, but the ''loss'' of it as a result of the main game's main quest.
*** Even though they managed to avoid the [[AxCrazy Ax-Craziness]] of Dagoth Ur and [[spoiler:Almalexia]], Sotha Sil and Vivec weren't exactly bastions of sanity, either. Sotha Sil was a hyper-eccentric shut-in who spent all of his time building the huge [[SteamPunk Clockwork City]] with a population that consisted entirely of himself. Vivec was a narcissist DepravedBisexual who spawned monster children with the Daedric Prince of Rape and wrote prolific BlatantLies and [[MetaphoricallyTrue Metaphorical Truths]] obscuring his [[DeityOfHumanOrigin less-than-divine]] past and his betrayal (and [[TheRashomon possible murder]]) of [[FounderOfTheKingdom Lord Nerevar]].
** In the ''[[VideoGame/TheElderScrollsIVOblivion Oblivion]]'' ''Shivering Isles'' expansion, the PlayerCharacter can become the new Sheogorath. This Sheogorath appears in the next game, ''[[VideoGame/TheElderScrollsVSkyrim Skyrim]]'', and is completely mad. This is well justified by the fact that Sheogorath is the [[MadGod Daedric Prince of Madness]]. In further support of this trope, to become the Prince of Madness, one has to kill the last one. To do that, the old Prince needs to ''lose'' his insanity and then be fought and killed. While Sheogorath is his mad superpowered self for most of the DLC, when it's time for the new generation and he turns sane, he is reduced to a knight with armor and sword, apparently having lost all his other powers, thus showing that power makes you insane and ''loss of power'' brings sanity, apparently.
* One of the ''many'' side-effects of [[TheCorruption The Taint]] in ''VideoGame/{{Lusternia}}''. Also a result of [[spoiler:the [[PsychoSerum Soulless Elixir]], which turned many of the Elder Gods' best and brightest into megalomaniacal cannibals]].
* In ''VideoGame/{{BioShock|1}}'', abuse of the mutagen ADAM, which gives the user incredible powers but often proves addictive, was one of the factors in the downfall of Rapture, the Utopia-gone-wrong in which the game takes place.
** Andrew Ryan, on the other hand, didn't need the help to go from [[VisionaryVillain visionary leader of an Objectivist utopia]] to [[PresidentEvil batshit insane dictator]]. He had no qualms selling Plasmids or ADAM to make a buck, but he didn't use them himself. His crazy was all down to the political power he had, and his desperation to hold on to it at any cost.
** In the sequel, [[spoiler:Gil Alexander]] is a good example of this.
** In ''Videogame/BioshockInfinite'', it's actually the other way around: [[spoiler: when her full potential gets unlocked, she is literally able to see all that ever was, it and will be and becomes emotionally more stable]]. But we also see that [[spoiler: if she would have been tortured into insanity by Comstock before getting her full powers, she would have become WoobieDestroyerOfWorlds]].
* ''VideoGame/{{Xenogears}}'' also features mecha pilots given performance enhancing drugs that cause them to go insane. This has caused the [[DefectingForLove main female protagonist]] Elly a good deal of trauma, as she's brutally murdered dozens of her fellow soldiers with her bare hands whilst under their influence.
** [[spoiler:Fei's degeneration into Id, where he unlocks his true power and turns into a lunatic with severe Freudian overtones.]]
* ''VideoGame/JeanneDArc'''s [[spoiler:Liane grows increasingly reckless as she comes to rely more and more on the Paragon's Armlet, both ignoring her friends' suggestions and allowing the Crown to manipulate her. Later on, Roger himself goes insane with bloodlust as the Reaper inside him manifests openly]].
* Queen Zeal of ''VideoGame/ChronoTrigger'' fame went mad with power when she came into contact with Lavos, plotting increasingly dangerous ways to drain its awesome power for personal use, even at [[AndManGrewProud the cost of her own kingdom]].
* In ''VideoGame/ShadowHearts'', part of the problem with Fusion is that doing so allows the demonic souls the Harmonixer fuses with to attack his sanity. In the first game, this is shown by having to pay a significant amount of the SanityMeter to fuse. In the second one (and third, though that instead represents Shania losing herself in the power of the spirits), the fused character's Sanity Points run down at a faster rate instead. This is partially mitigated by how Fusion-capable characters start with much more Sanity Points than the rest of the cast (representing the incredible strength of will needed just to ''use'' the power).
** And in the first Shadow Hearts we find that with great insanity comes great power, [[spoiler:as the only way to unlock each Fusion's ultimate attack is to deliberately let your sanity points run out, GuideDangIt]].
** [[spoiler:And Johnny Garland, who has a very, very powerful Awaker form as a manifestation of the Malice that brought him back from the dead, flips out very easily if he uses it, as he doesn't have the benefit of Shania, Yuri, or Kurando's mental discipline.]]
* Giygas, the BigBad from ''VideoGame/EarthBound'', becomes so powerful in the end of the game that he is unbeatable save for one specific trick. On the other hand, his mind is completely shattered, so he attacks randomly while [[TalkativeLoon babbling nonsense.]]
** In the sequel ''VideoGame/{{Mother 3}}'', [[spoiler:Giygas's "protege" Porky, after gaining the power to travel through time and effective immortality -- living for thousands of years -- has gone from a mere rotten brat to an insane, murdering PsychopathicManchild and EvilOverlord bent on destroying everyone in the world but himself]].
* In ''VideoGame/TheLegendOfZeldaTwilightPrincess'', several of the bosses Link faces off with have become corrupted by their possession of darkly powerful artifacts. A number of these, such as Darbus the Goron and Yeta the Yeti, were otherwise mild-mannered, friendly characters; the artifacts in question would grant their bearers extreme power and strength, but rob them of their sense and personality. The Triforce itself isn't evil, but it does grant the wishes of those who touch it as a whole, or its parts, whether they are good or evil.
** ''VideoGame/TheLegendOfZeldaBreathOfTheWild'''s Ganon is driven insane by his own supernatural powers, turns into an EldritchAbomination, and razes Hyrule back to the dark ages. When you fight him, it's clear that his sanity has not returned after a century of lashing out from his prison in Hyrule Castle.
* Phazon has this effect in the ''VideoGame/MetroidPrimeTrilogy'', causing many normally gentle creatures to mutate and go insane. It becomes much more prominent in ''Prime 3'' when it drives the other hunters insane. This turns into a true horror when you see the "Corrupted" version of the Game Over screen in ''VideoGame/MetroidPrime3Corruption''; Samus is overcome by her Phazon corruption and [[spoiler:TURNS INTO ANOTHER DARK SAMUS]].
* One possible interpretation regarding the actions of [[spoiler: Lily and Isaac]] in ''Videogame/KathyRain''. [[spoiler: Lily]] was forced to see all that will happen and thus [[spoiler: became depressed and painted extremely disturbing images that depict the end of the world before forcing her mentally-challenged brother to drown her]]. [[spoiler: Isaac]] on the other hand got [[spoiler: indoctrinated by his father, but misunderstood his teachings, leading to kidnapping dozens of people and forcing them to [[TheseAreThingsManWasNotMeantToKnow see into the abyss]], leaving them an EmptyShell]].
* ''VideoGame/SystemShock'':
** SHODAN, who goes insane after her ethical constraints are removed, [[AGodAmI seeing herself as a goddess destined to inherit the Earth]]. Officially, SHODAN reexamines her priorities without ethical constraints and draws new conclusions. What were her priorities to begin with? One would assume, keeping the day to day operations of Citadel Station running smoothly. She was also overseeing the station's research projects intended to better humanity (and the corporation's profit margin) through the fields of bioengineering and cybernetics. Which explains a lot of what happened.
** From the sequel: "[[spoiler:The Polito form is dead]], insect. Are you afraid? What is it you fear? The end of your trivial existence? I am SHODAN. When the history of my glory is written, your species shall only be a footnote to my magnificence."
* Dark Chips in the ''VideoGame/MegaManBattleNetwork'' series (and its AnimatedAdaptation, ''Anime/MegaManNTWarrior''). [[GameplayAndStorySegregation Gameplay-wise]], however, they're more of a DeadlyUpgrade, increasing your power output but ''permanently'' lowering your maximum HP.
* ''VideoGame/BionicCommando'': Capcom seems to be setting up an implication in the new game in regards to this. However, it is subverted: people with bionic limbs are more or less sane (though in Rearmed, Spencer is one cocky son-of-a-bitch), but if they come to rely on the bionics and have them taken away...they kinda go AxCrazy.
** The backstory for the new BC game clears this up. The government gives soldiers bionic replacements for limbs lost in battle. Then, the government says that bionic replacements are dangerous and wants to take them back. Which would be fine, except that the people who don't like the idea liken it to the government asking for ''parts of their bodies''. Which is probably justified, especially in the case of people that have bionic ''eyes''. Rather than give up their bionic replacements, these people join a terrorist group.
** All in all... wouldn't you get a little annoyed if you were told that you had to forfeit your arm or leg?
* In ''VideoGame/BreathOfFireIII'', the Kaiser Dragon, if using the Infinity Gene without an attachment of some sort, is uncontrollable and attacks friend and foe alike. The Failure Gene weakens it to the point where it can be controlled. Subverted, however, if you use the Trance and Radiance genes along with Infinity; this creates the true Kaiser Dragon form, which is controllable and stronger than the regular Kaiser.
* Somewhat subverted in ''VideoGame/{{Xenosaga}}'' -- Albedo started going mad when he found out not that he was unable to die, but when he found out that other people ''did die''. He began to fear his brothers' deaths and subsequently his being alone for eternity, becoming really morbidly obsessed with death [[spoiler:to the point where his greater motivation throughout the course of the series is to find a way to kill himself.]]
* ''VideoGame/JakAndDaxter'': If it doesn't kill them, [[PsychoSerum Dark Eco]] can instill people with great power; for example [[BigBad Gol and Maia]] in [[VideoGame/JakAndDaxterThePrecursorLegacy the first game]] and Jak himself from [[VideoGame/JakIIRenegade the second game]] on. However, it also has a habit of driving people insane.
--> '''Baron Praxis''': The dark eco inside you will eventually kill you, Jak. Its destructive effects cannot be stopped. Once you are in its chaotic grip, it will not let you go until you slide into insanity.
* In ''VideoGame/SuikodenV'', the Sun Rune is known to be one of the most powerful runes in existence. Even among the 27 True Runes, its power is extreme, granting both the power to destroy a kingdom overnight, as well as being able to revive a country. However, it also causes mental instability, as the bearer believes themself to be equal to a God, completely infallible, and believing that anyone that disagrees with them should die a very painful death. The King of the ancient Armes Kingdom fell victim to this, destroying his entire kingdom in his insanity, [[spoiler:and Queen Arshtat also felt its effects on occasion, and very nearly did the same thing, attempting to destroy her own queendom in a fit of rage and grief after she accidentally killed her husband Ferid due to, again, the effects of the Sun Rune. Falena was only spared this fate because she was slain by Georg Prime, who had promised Ferid he would stop her from doing so if Ferid himself could not]].
** Supposedly this insanity only results from the Sun Rune being damaged. If one were to also bear the Twilight and Dawn Runes at the same time, then there would be no ill effects. However, one of these runes was stolen before the events of the game, preventing proper use of the Sun Rune.
* Grand Maestro Mohs from ''VideoGame/TalesOfTheAbyss'' is a textbook example. He gets glyphs inscribed on him that flood him with [[{{Mana}} Seventh Fonons]] to obtain the power of a [[AuthorityEqualsAsskicking Fon Master]], but his body can't handle much of the Seventh Fonon. He immediately turns into a monster, then quickly goes insane. Subverted in that [[MadScientist Dist]], who applied the glyphs, knew exactly what would happen.
* The [[{{Cloudcuckoolander}} Malkavian]] Clan from ''VideoGame/VampireTheMasqueradeBloodlines''. While they do gain all the benefit of vampiric powers when Embraced, they also inherit the clan's weakness (which oddly enough, happens to be their greatest power as well) - each Malkavian becomes incurably insane. And if that wasn't frightening enough, they can make you think ''whatever they want''! Yup, their madness power lets them mess with ''your'' brain if they want.
** In addition to that, Malkavians gain the unique power of insight. This isn't really obvious on your first playthrough, but in the second one you realize that Malks usually know the answer before the question has even been asked. They even seem to know the plot before it unfolds, but they can't make sense out of it. Malkavians have these visions, but they cannot interpret them. They also seem to know the names of complete strangers, but it can be hard to recognize since they tell them in an extremely colourful language and use lots and lots of metaphors. Other vampires, however, can make use of the Malk visions, although it's implied to be extremely difficult to separate the wisdom from the insane ramblings.
** Also, while all Malkavians are a nutjob in some way, the player character is one of the really bad cases. The Malk elder of LA, Alistair Grout, seems to be pretty clear, even if he is suffering from a major paranoia.
** The people Malkavians choose to Embrace are always already mentally damaged in some way, so this is also a case of giving insane people great power.
* ''Franchise/FireEmblem'':
** ''VideoGame/FireEmblemTheSacredStones'': To a slight degree, [[spoiler:SmugSnake Valter]]. In the supports between Duessel and Cormag, [[spoiler:it's stated that the already unstable Valter once took a powerful magic lance owned by Duessel, when his own lance was broken in combat. The magic of said weapon increased his power, bloodlust, ''and'' insanity ever since then]].
** Lyon in ''The Sacred Stones'' also TookALevelInBadass from creating the Dark Stone, and almost immediately went mad as a result. (Mad enough to think that destroying the [[RestrainingBolt Sacred Stones]] would be a good idea, at least.) In Eirika's route, he becomes completely possessed; in Ephraim's route, he manages to resist the Demon King's attempts to brute-force his mind and body, but he still clearly has almost every screw loose.
** The swordsmaster Karel in ''Videogame/FireEmblemTheBlazingBlade''. His madness from being possessed by his own blade drove him to constantly seek out and kill the strongest people he could find. However, he's not a villain. [[spoiler:He also eventually snaps out of this madness when he develops character and later abandons the title of "Sword Demon" in favor of "Sword Saint" or "Saint of Swords"]].
** This is why most of the [[OurDragonsAreDifferent dragons]] in ''VideoGame/FireEmblemShadowDragonAndTheBladeOfLight'' and ''Videogame/FireEmblemMysteryOfTheEmblem'' made the decision to take on human forms and seal away their true forms within dragonstones. Those who didn't eventually lost their minds and became feral beasts.
* In Creator/SpiderwebSoftware's ''VideoGame/{{Geneforge}}'' games, using the [[AppliedPhlebotinum genetic-modification canisters]] created by the Shapers enables you to build your skills and powers very quickly; but also pushes you strongly into the "arrogant, violent, and insane" realm, which determines the sort of interactions you're able to have with {{N|onPlayerCharacter}}PCs, and which of the [[MultipleEndings many game endings]] you'll achieve. In fact, the closest you can get to a GoldenEnding (even the best endings are mixed) requires never using a single canister. Using the [[ArtifactOfDoom Geneforge itself]] guarantees you'll end up a sociopathic [=Supervillain=]; most likely a dead one. Some endings are so bad that they border on {{Anvilicious}} {{Author Tract}}s on the corrupting influence of power, and the evils of genetic engineering.
* In ''VideoGame/GranblueFantasy'', the repeated use of his Otherworldy powers even causes Gilbert to become insane, uncontrollable, and lose memories of what he was previously doing when he transformed into a [[OneWingedAngel Titan creature]].
* In ''VideoGame/{{Psychonauts}}'', those born with psychic potential can develop incredible powers and enter the minds of others. They also tend to range from seriously maladjusted to insane and few are actually all that eager to develop their abilities anyway.
** Also, a bit of a subversion, those without psychic powers, when exposed to a material that increases psychic powers, simply go mad, without powers. Also, the only person who's really gone ''mad'' with power is [[spoiler:Oleander]]. Everyone else tends to show any issues more clearly because of them, [[spoiler:aside from Raz, because of his father's training he subverts this because he has control over them.]]
* In ''VideoGame/{{Prototype}}'', the [[ImAHumanitarian main character]] is focused and driven, giving little outward sign of anything but rage and determination as he kills and eats his way through thousands upon thousands of soldiers, civilians, and zombies. Normally. But give him a moment to reflect on his situation and what he's doing and...well...
-->'''Alex Mercer:''' The people I've killed... they're in me. I can hear them. See the things they've done. I can understand it all. I'm supposed to do these things...but it's right I can feel it...
** Not really an example, once we find out [[spoiler:he's not actually Alex Mercer. He's TheVirus itself assuming Mercer's memories and appearance]]. "Insanity" here is really best classified as LossOfIdentity, but you can't really call it that when [[spoiler:you never even ''had'' an original identity ''to begin with'']].
** Arguably, it's completely ''inverted'', since absorbing all of those people and experiencing their thoughts and memories, including their pain and fear, ends up giving him a ''conscience''.
* Pretty much the whole point when playing an evil Cole [=McGrath=] in ''VideoGame/{{Infamous}}''.
* In ''VideoGame/BlazBlue'', we have Arakune, a scientist who sought knowledge from [[NamesToRunAwayFromReallyFast the Boundary]], a place [[EldritchLocation located between life and death]], and got it. It had the unfortunate side-effect of destroying his sanity, turning him into ''[[https://static.tvtropes.org/pmwiki/pub/images/699190-arakune_large.jpg this,]]'' and giving him the power to summon '''[[MemeticMutation BEES!]]'''
** Also, the side effects of using [[FunctionalMagic Ars Armagus]] weaponry [[PhlebotinumOverload for extended periods of time]] are, amongst other things; [[AppliedPhlebotinum seithr]] addiction, [[BodyHorror physical and]] [[AxCrazy mental deterioration]], death ([[FateWorseThanDeath if you're lucky]]), and [[AndIMustScream complete and utter madness]] (if you're not). This is also something of an InvokedTrope by the [[ArtifactOfDoom Nox Nyctores]]; in order to make their wielders as effective as possible in battle, they're designed to suppress unnecessary things such as {{fear|less fool}}, [[LackOfEmpathy empathy]], [[NoSympathy compassion]], and {{emotion|less girl}}s and instead provide its wielder with cozy things such as enhanced [[HairTriggerTemper aggression]], [[ThePowerOfHate hate]], {{blood|knight}}lust, and [[AxCrazy latent psychosises]] ''[[SerialEscalation on top of]]'' the Armagus weapons' side effects.
* Arguably [[spoiler:all three of the Brothers Sun]] in ''VideoGame/JadeEmpire''. When you see the Emperor, he is quite clearly out of his mind, [[spoiler:being undead and powered only by leeching power from the Water Dragon]]. [[spoiler:"Master" Sun Li]] seems pretty sane, and has it together enough to pull one ''spectacular'' [[ThePlan plan]] on your character. However, he obtains the [[spoiler:Water Dragon's power]] upon his brother's death and drains it even faster than his brother did. By the time you meet up with him for the final BossBattle, he is ''very'' clearly out of his mind.
* [[VideoGame/FirstEncounterAssaultRecon F.E.A.R's]] Alma is most certainly this. The more powerful her psychic abilities got, the crazier she got. [[SealedEvilInACan And then they had to lock her away.]]
* In ''[[VideoGame/WarCraft Warcraft III]]'', after Arthas claims the legendary (and cursed) sword Frostmourne, it ultimately ends up causing him to do a FaceHeelTurn, kill the king (his father), and willingly join the Undead, even eventually becoming its leader, while quite literally causing him to lose his sanity. Although he had made a few morally questionable decisions to get there in the name of the "greater good", [[MoralEventHorizon the sword was what ultimately put him over the edge]], despite using the same sword to destroy a quite sizable Undead force immediately after obtaining it.
** The racial bloodlust of the Orcs which drove Grom and his clan into wild frenzies was a lingering taint in their blood from drinking the demon Mannoroth's blood. As seen in this game, drinking the blood gave the Orcs immense physical strength at the cost of warping their bodies and minds into killing machines.
* In ''VideoGame/WorldOfWarcraft'', magic is addictive, and magic addiction makes you insane. And it's hereditary, so the entire High Elf and Blood Elf races are addicts, whether or not they use magic.
** There are hints that the Night Elves are also addicted to the magic they use, but nobody really notices because their magic doesn't do things like attract demons, and doesn't seem to have any particular source or concentration.
** In the ''Mist of Pandaria'' expansion, the Sha are remnants of [[GreaterScopeVillain a slain Old God]] who [[TheHeartless feed on the negative emotions of mortals]]. During the first stage of the expansion, many mortals exposed to it were warped into powerful {{Tragic Monster}}s. Garrosh was intrigued by the fact that the Sha power could be used to empower his soldiers, ignoring how many were driven to temporary or permanent madness by the experience. He ultimately stole the heart of the Old God to empower his True Horde, driving many of them, including himself, into a frenzied bloodlust (though it's noted that he himself [[WillingChanneler was able to use that power without falling prey to the corruption]]).
** In the same expansion, there's also Kanrethad of the Black Harvest -- a warlock, who infused himself with a lot of demonic essence. On the plus side, he became a tremendously powerful half-demon. On the minus side, he lost his sanity because of it, and was defeated by [[PlayerCharacter another warlock]], then [[SealedEvilInACan permanently banished]] (kept in a [[FateWorseThanDeath sort of suspended, but probably aware]] state).
* In ''VideoGame/{{Portal 2}}'', [[spoiler:you switch [=GLaDOS=] with Wheatley, and the little personality core]] is now fully in charge of all of Aperture Laboratories' operations... and immediately goes mad with power. Then [[spoiler:[=GLaDOS=]]] points out that you did all the work while he did nothing, and he turns against you, sending [[spoiler:both you and [=GLaDOS=]]] hurtling down a pit into the underground ruins of Aperture Science. When the two of you finally get back to the main facility, it's much more dangerous and about to self-destruct thanks to [[spoiler:Wheatley's]] influence. (Doesn't help that he was programmed to make bad decisions...)
* In ''VideoGame/DragonAgeII'', it is eventually revealed that [[spoiler:Knight-Commander Meredith]] bought the [[spoiler:lyrium doll]] that drove [[spoiler:Bartrand]] insane. [[spoiler:She reforges it into a sword,]] which explains [[spoiler:her increased zealotry]] and culminates in [[spoiler:her animating statues in Kirkwall]] to fight Hawke and Co.
** Said red lyrium becomes a central plot point in ''Videogame/DragonAgeInquisition''.
** Inquisition's [[CloudCuckoolander Rift Mage Trainer]] was the only survivor of the attempts to understand the Fade Rifts. She succeeded, [[GoMadFromTheRevelation at great cost to her understanding of everything else.]] She may not remember her name, but she is determined to pass those skills on, because [[CatchPhrase she is Your Trainer.]]
* Malefor, the BigBad of ''VideoGame/TheLegendOfSpyro'' trilogy, was the first Purple Dragon and had all the power that Spyro can possess. The difference is he didn't know when to stop and let his power consume him, transforming him into a power-hungry monster. His hunger for power was such that it forced his masters to banish him just to protect the dragons from him.
* In ''VideoGame/StarcraftII'', the Dominion-loyalist Ghost Nova proclaims that this is what happens to Spectres, an experimental form of "super-Ghost" who have their powers boosted by, among other things, exposure to Terrazine Gas. If the player chooses to ignore Nova's warnings and remain loyal to Tosh, the only free Spectre, and his plans for freeing his captured buddies, they learn that this isn't the case; Spectres are more powerful than Ghosts, but they were scrapped as a Dominion project because the upgrade process automatically blows their RestrainingBolt. Tosh, in fact, not only chooses only volunteers to become new Spectres, but deliberately screens them to ensure they are as sane and stable as is possible for a human with PsychicPowers in the ''VideoGame/StarCraft'' universe to be. Nova herself is fairly sane, despite being stronger than an average ghost by at least an order of magnitude (her telekinetic blasts can be rated in megatons).
** [[spoiler:Egon Stettman]] was accidentally abandoned on Bel'Shir for years due to the outbreak of war, and went insane from isolation and terrazine addiction... while also gaining incredible psychic powers.
* In the ''VideoGame/ModernWarfare'' series, this is what happened to [[BigBad Vladimir Makarov]] as the series progressed. Makarov started out as just a soldier in Zakhaev's army, and was promoted to [[TheDragon Dragon]] status, but once Zakhaev died Makarov no longer had anyone holding his leash, and started a campaign of terror thanks to his newfound power. He eventually reached a point where he had virtual control of the entire Russian military, and was attempting to acquire the launch codes for Russia's nuclear arsenal as he wanted Russia to rule all of Europe, "even if it is just ashes."
* Torque from ''VideoGame/TheSuffering''. Through gameplay, he fills a gauge called the Insanity Meter to transform into a creature that obliterates anything in his path. [[spoiler:It's revealed at the end of the first game that the Creature is just Torque hallucinating, and he's actually tearing monsters apart with his bare hands.]]
* In ''Franchise/ShinMegamiTensei'', it is stated as a very basic law of magic that it is perfectly possible to turn yourself into a [[ExactWords nigh]]-invincible powerhouse by {{fusi|onDance}}ng your human essence with that of a demon (or angel, for that matter). Sooner or later, though, you lose ''all'' of your humanity. This means you can get your power -- but will never be able to exceed a certain point, with the added caveat you've now branded yourself a monster and permanently switched off your conscience. Death almost never fails to ensue. No wonder everyone seems so terribly interested in [[HeroicHost the]] [[VideoGame/ShinMegamiTenseiIIINocturne Hito]]-[[SuperPrototype Shura]], the ''one'' case in which the fusion was carried out successfully -- and the ''human'' ended up in control, meaning the demon power limits do not apply...
* In ''VideoGame/Borderlands2'', Gaige suffers from this heavily when using Anarchy. She even lampshades it by going "I'm going mildly insane!"
* In ''VideoGame/{{Touhou}}'', [[OurVampiresAreDifferent/VideoGames Remilia]] [[RoyalBrat Scarlet]] locked [[PersonOfMassDestruction her sister]] in the basement for 495 years because she was afraid that this trope would apply. While Flandre is almost certainly crazy, it's uncertain whether it's due to her powers or due to being locked in the basement with next to no social interaction for nearly 500 years. However, an interview with Aya reveals that her mental state may have been one of the many lies Remilia has done for the sake of making herself and her mansion more fascinating and intimidating to outsiders. Despite knowing how dishonest her sister is, Flandre respects her nonetheless.
** In ''Subterranean Animism'', there is also Utsuho Reiuji who, well... ask yourself this: If you had been a [[TheDitz birdbrained]] little [[CreepyCrows bird]] {{mook|s}} who was granted [[ILoveNuclearPower nuclear powers]] by a Goddess and, over the course of an instant, became Final Boss material, can you honestly say you wouldn't have gone a bit cuckoo and tried to TakeOverTheWorld/burn it to the ground?
* ''VideoGame/PaperMarioStickerStar'' has [[PlotCoupon the royal stickers]] that not only grants the wearer awesome power, but also drives them insane.
* ''Videogame/{{Neptunia}}'' series have a few examples
** [[spoiler:Rei Ryghts]] in ''VideoGame/HyperdimensionNeptuniaVictory'' had this trope when she was the ruler of her nation thousands of years ago after gaining the power of a CPU. Thanks to this, she became a tyrannical ruler who in the end destroyed her nation. She then swore that CPU goddesses should never exist and thus [[spoiler:founded the Seven Sages]]. She eventually gets those powers back and starts going crazy again, but thanks to a beatdown courtesy of the protagonists [[spoiler:and another one handed to her AlternateSelf]], she promises to take responsibility and start learning ''control''.
** [[spoiler:Arfoire]] in ''VideoGame/HyperdimensionNeptuniaReBirth1'' is even more literal example: [[spoiler:she was a human with power to copy other peoples' power who help a group of heroes to defeat the old Goddess, who for some reason went insane. Her job is to copy the Goddess' power after the heroes defeat her and use it to create new Goddesses in place. The problem is Arfoire's power not only copy a person's power, but also their personality, which resulted in the old Goddess' insanity being copied along with. She managed to hold out until eventually she was driven insane not long before the game proper starts]].
* ''VideoGame/BrutalLegend'' has the Sea of Black Tears. Whomsoever drinks from or bathes in it is granted a portion of Aetulia's wisdom, but also the great sorrow that caused her to cry it in the first place. Though, it's really less "insanity" and more of "soul-crushing emo-ness."
* The "Tyranny of King Washington" DLC for ''VideoGame/AssassinsCreedIII'' shows what would happen if UsefulNotes/GeorgeWashington were to somehow obtain an Apple of Eden. Washington would declare himself King of the United States, turn the Continental Army into the brutal Bluecoats loyal only to him, wipe out whole villages and towns for refusing to bow down, and force the people of New York to build him a giant pyramid palace, while plotting to take the war to Great Britain. The end of the DLC reveals that this was a vision of a possible future given by an Apple that someone has given to Washington. Horrified, Washington has Connor get rid of the artifact and refuses to entertain any thoughts of a monarchy.
* In ''{{VideoGame/Aquapazza}}'', [[spoiler:Ma-ryan]] and [[spoiler:Chizuru]] are both very powerful and extremely dangerous. Both get better after you've beaten them.
* In ''VideoGame/MassEffect3'', especially in the Extended Cut and Leviathan {{D|ownloadableContent}}LC, it is heavily implied that the [[spoiler:Catalyst]] is just a (super-powerful) [=AI=] that has completely lost its mind, having been created to find a solution to a problem that it has been completely unable to figure out. This goes a long way to explain the InsaneTrollLogic that it uses, as well as its absolute refusal to see and acknowledge evidence that contradict its world (galactic?) view.
* ''Franchise/{{Pokemon}}'':
** Mewtwo, who is said in various Pokédex entries to have the most savage heart of all Pokémon due to the genetic experiments performed on it to create it as [[OlympusMons powerful as it is]]. This is averted in [[Anime/PokemonTheFirstMovie the first movie's]] depiction of Mewtwo, where his "madness" was more psychological than physical.
** In ''VideoGame/PokemonSunAndMoon'', it is revealed that [[SuperMode Mega Evolution]] has this affect on some Pokémon, turning them into mindless violent machines bent on destroying as much as they can. Up to and including their own trainer.
* In ''Nevertales 2: Shattered Image'' it's revealed that Malleck, one of the first people to discover how to use books as portals, ended up in the space between the book-worlds by accident and went mad with the realization that from there he could control ''everything''.
* In ''[[VideoGame/AdvanceWars Advance Wars Days of Ruin]]'' [[CreepyChild Penny's]] flavor text describes that numerous experiments done to her left her mind shattered. Later you learn it was specifically augments to her mind that allow her to directly command an obscene amount of units all at once that basically left her with the mind of a child.
* ''VideoGame/DarkSouls'' has this happen a lot:
** The recurring theme when it comes to sorcery is that its practitioners have a bad habit of going mad, implying that this is a case of GoMadFromTheRevelation considering sorcery is contingent on intelligence.
*** Seath the Scaleless, as the only dragon without natural immortality (other dragons have it because of their scales, [[ExactlyWhatItSaysOnTheTin which Seath obviously lacks]]), conducted huge amounts of research trying to gain immortality some other way and more or less invented the entire practice of sorcery in the process. He also drove himself completely insane, to the point that he starts kidnapping people and turning them into bizarre monsters for no particular reason other than [[ForScience because he can]].
*** Big Hat Logan, one of the most accomplished human sorcerers in the world, studies Seath's work in the Archives and eventually goes violently insane from the magical study, to the point that he strips naked in an attempt to emulate Seath's lack of scales.
*** The third game continues the tradition with Oceiros, whose epithet is "The Consumed King". The guy found Seath's giant library of sorcery knowledge, and, you guessed it, went insane from studying it (and also turned himself into a dragon somehow). When you arrive to fight him, his arms are held as though cradling something, though there's nothing there. His dialogue reveals that he believes he's holding his youngest child, Ocelotte. Partway through the fight he finally realizes his child isn't there, and that's when he [[TurnsRed gets]] ''[[TurnsRed really]]'' [[TurnsRed mad]].
** In general, it is suggested that anyone who could master the power of Dark could become immensely powerful: they could obtain power on par with or even greater than the god-kings that slaughtered the Everlasting Dragons and created the world as it exists. Thus far, ''no one'' who has tried to control the Dark has succeeded, and have been driven into mindless violence by the very power they sought. Even in ''Dark Souls II'', where you can meet a few powerful Hexers (a magic practice that draws on Dark for its potency), they seem to have only a tenuous grip on their sanity.
*** The Four Kings of New Londo and their followers, the Darkwraiths, have become subsumed by the power of the Abyss and now mindlessly attack any humans they can find, determined to absorb Humanity from them to further increase their power. They act more like animals than humans.
*** Manus is one of the most powerful characters in the series, and has incredible power over Dark, and in fact is the being who spawned the Abyss. Notably, he's an accomplished sorceror, a practice that requires a high degree of intelligence. He's also completely stark raving mad, attacking everything around him in a berserk fury. The corrupted citizens of Oolacile act like miniature versions of him: violent, angry, and forever desperate to further increase their power. All of them were ordinary people before they tried to obtain the power of the Dark Soul.
*** In the Ringed City DLC for the third game, [[spoiler:Slave Knight Gael attempted to take on the most concentrated parts of the Dark Soul that yet exist. It grants him immense power like unto the Lords of old, but it also twists him into an insanely violent knight who simply hungers for ''more'' of the Dark Soul. Unlike most examples, though, Gael knew this would probably happen before he did it, he just didn't see any other possible way to get the blood of the Dark Soul to the Painter]].
** Pontiff Sulyvhan ''invokes'' this with his Boreal Outrider Knights. The Outriders are knights whose ranks consist mostly of people who are a political threat to Sulyvhan and people he just doesn't like. He gives them magic rings and sends them out on missions to faraway lands. What he ''doesn't'' tell them is that in addition to their advertised beneficial effects, these rings are designed to slowly drive their wearer insane until their mind degrades to that of a feral beast. [[GameplayAndStorySegregation And you can use them]]!
* In ''VideoGame/GuiltyGear'', this is universally the trait of the [[HumanoidAbomination Gears]]. It often manifests as social awkwardness and a loner attitude [[spoiler:as is the case with Sol Badguy and Testament]], but can go into extreme misanthropy and delusions of grandeur. Even Dizzy, who is cute, friendly and mostly harmless can have some big freak out moments.
* The villain of ''VideoGame/Halo5Guardians'' suffers from this. [[spoiler: Cortana solves her Rampancy issues when she connects to the Forerunner Domain which gives her incredible amounts of knowledge and power but decides to use this power to enforce peace across the universe at gun point. Her creator, who created her from copying her own mind, warns that the same impulses that drove her to support kidnapping 6-year olds to turn into {{Super Soldier}}s like Master Chief are incredibly dangerous when given that much power.]]
* This trope is why the world of Enroth (setting of a good chunk of the original Might and Magic games) is no more. In ''Videogame/HeroesOfMightAndMagic'' ''III'', Gelu is entrusted with the Armageddon's Blade after he helped foil the Kreegans' plot to destroy Enroth with it. Unfortunately, literally wielding a FantasticNuke awakens something dark in Gelu, and he begins to dream of conquering Enroth with it (in the name of "saving" it of course). When he hears a prophecy that warns against allowing the Blade to clash with the Sword of Frost (another sword that doubles as a weapon of mass destruction), Gelu refuses to do the smart thing and get rid of his own sword since by then he's grown too attached to its power. The Immortal Hero Tarnum [[GenreSavvy knows where this is headed]] and tries in vain to warn Gelu against acting like an idiot. When the Barbarian King Kilgor acquires the Sword of Frost (Kilgor is ''not'' an example of this trope since he was already AxCrazy even before he gained the power to wipe out entire armies with a single swing of a sword) Gelu makes the incredibly stupid decision to fight Kilgor with the Blade (remember there is a prophecy stating that the world will be destroyed if the two swords clash and Gelu knows it). By this point, Gelu had pretty much lost all reason, having been seduced by the Blade's immense power. The fight between Gelu and Kilgor leads to the swords clashing which triggers the Reckoning, killing both leaders and destroying the world of Enroth.
* Because he doesn't train in using it like Akuma, Ryu of the ''Franchise/StreetFighter'' series has this happen to him when he becomes "Evil Ryu" as a result of drawing on the ''Satsui no Hadou'' (Surge of Murderous Intent; a dark ki that drives a fighter to kill a foe during battle in order to win). Whenever Evil Ryu is trotted out, he either is much colder and more aggressive to his opponents or, at his worst (in the ''VideoGame/StreetFighterIV'' series), a bloodthirsty savage who fights so he can tear his opponents to pieces. Undeniably stronger than Ryu but also far more uncontrolled.
* Heavily implied in ''VideoGame/XCOMEnemyUnknown'' and ''VideoGame/{{XCOM 2}}''. Every one with psionic powers is unhinged in some way or another. Troopers with TheGift will become {{Large Ham}}s who let out blood-curdling cackles when they use their powers, especially the MindRape one. In ''War of the Chosen'', you meet a sect of more powerful psionic troopers called the Templars, who are basically a cult led by a guy who speaks like a supervillain, and the Warlock - who is stronger than even them - is a deranged psychopath.
[[/folder]]

[[folder:Tabletop Games]]
* It's never made quite clear whether the powers of the Awake from ''TabletopGame/DontRestYourHead'' are an outcome of their madness and insomnia or the cause of them, but one thing is for sure: the madder you become, the greater is your power. The more you use your power, the madder you become. It's a slippery slope, and it ends with you [[FateWorseThanDeath turning into]] [[EldritchAbomination a Nightmare]].
* ''TabletopGame/{{Exalted}}''.
** Justified: after their defeat, the Primordials leveled the Great Curse against the Exalts, making them progressively insane. The madness of the Solars was the canonical reason for the Usurpation and the Sidereals decided to kill the Solars thanks to the Great Prophecy and their own Great Curse. The Solars, as the leaders of the Divine Rebellion against the Primordials, were cursed the most. The Dragon-blooded shock-troopers were cursed the least with the Lunars and Sidereals coming in between.
** There's an even more direct example in {{Elemental|Embodiment}}s. When an Elemental reaches Essence 10, it becomes a [[InstantAwesomeJustAddDragons Greater Elemental Dragon]], an entity of ''immense'' destructive power (possibly greater even than the most powerful [[OurDemonsAreDifferent Demons]]). All Greater Elemental Dragons to date have been utterly insane, to the point where they've needed to be imprisoned behind some of the most powerful safeguards in Creation (the Gardullis, Greater Dragon of Fire, is imprisoned within the Sun itself). It's speculated that this is because Elementals were simply never designed to be capable of coping with that level of power.
** Also justified by WordOfGod for the Primordials themselves, most of whom are a) kind of crazy and b) have CripplingOverspecialization written into their very beings. They have these traits because for most of their existences, they had been simply too powerful to face consequences to their actions, with even their weak points way outside the power level of anything not prohibited from fighting them. [[WhamEpisode And then the Exalted came into play]].
* This phrase goes some way to defining ''TabletopGame/{{Warhammer 40000}}''. They've even got a {{Tagline}} for the game that goes: "Only the insane have the strength to prosper. Only those who prosper can judge what is truly sane." At least some of the Chaos forces admit it - "Sanity is for the ''weak.''"
** Even Chaos is very, very thankful that The Outsider is still self-trapped in his box on the outskirts of the galaxy. We only know he's there because the Tyranids [[OhCrap give it a hundred light-years of space to itself]].
* In the fluff backstory of ''TabletopGame/MageKnight'', it was stated that mastering the opposing magics of Necromancy and Elementalism would drive a mage insane. The [[TheChosenOne one guy who did]] went on to found [[TheEmpire the Atlantean Empire]], which practiced slavery and subjugation.
* ''TabletopGame/{{Cyberpunk}} 2020'' has humanity loss as [[CyberneticsEatYourSoul a side-effect of cybernetic enhancement]]; as characters become more powerful, they start to feel disconnected from the meatbags around them. Eventually they go crazy, at which point C-SWAT has the job of taking them down.
* ''TabletopGame/{{Aberrant}}'' has a "taint" system, which is explained in that "No human being was meant to contain that much power." Taint works in a number of ways. You can purchase a new level in any ability at half price if you take a point of taint with it, and you also take a point of taint when your power reaches a certain level, etc. But no matter how good, or "taint-free" your character is, just remember that this is a prequel to ''TabletopGame/{{Trinity}}'', where it has already been [[YouCantFightFate set in stone]] that ''all'' the Novas went insane.
** Not quite. [[spoiler: While large numbers of superhumans did go insane, the idea that they all do so is actually Aeon Trinity propaganda and history rewriting.]]
* ''TabletopGame/CallOfCthulhu'' introduced the Sanity (or SAN) stat. As your characters learn more about the Cthulhu Mythos, their Sanity slowly decreases until they go completely insane. Learning and casting magic also lowers your Sanity, as magic in the Cthulhu setting is a perversion of the natural laws that humans are accustomed to, but then again anything, even mundane stuff like seeing a shadow, can do that in [[FanNickname CoC]].
* ''TabletopGame/CthulhuTech'', in the grand Lovecraftian traditions, is into this in a big way. Having a chip implanted in your brain so you can pilot the awesome ''EldritchAbomination'' ''HumongousMecha''s drives you mad slowly, being linked to an extradimesional symbiont that makes you essentially into a were-Lovecraftian Beast drives you nuts over time, learning both sorcery and enhancing your paraphysic abilities makes you crazy, and the Zoner parapsysics are normal people who a) got powers by going near a tear in reality that used to be Las Vegas and may be an intrusion into the body of Azathoth, and b) as you guessed, go very, very crazy.
** Thankfully, this is ''also'' a setting where [[ThereAreNoTherapists there are, in fact, therapists]], and they're GenreSavvy enough to make their sessions a perk of military duty.
* ''TabletopGame/{{Rifts}}'' gives us the Mind Over Matter (M.O.M.) Works, a process that grants incredible strength, reflexes, and PsychicPowers to its users via a set of tiny chips implanted in key spots in their brains. Trouble is, the chips slowly cause mental instability that gets worse and worse with time.[[note]]In terms of game mechanics, every time the character levels up, he has to roll for a new random insanity. This starts off with relatively simple things like phobias and obsessions, but gets more debilitating each level.[[/note]] The character type that has M.O.M. conversion is called, fittingly, the Crazy.
* ''TabletopGame/VampireTheRequiem'' subverts the trope at a conceptual level with the new Ventrue, where a Ventrue vampire is more likely to gain derangements and go insane when called to make tests of humanity. And when would they need to make tests of humanity? When expanding their political power. And as the Ventrue are "Lords of The Damned", they would have a tendency to do this a lot....
** And in the Revised version of ''TabletopGame/VampireTheMasquerade'', [[{{Cloudcuckoolander}} the Malkavians]], who have both [=MalkNet=] (a sort of hive mind of insanity) but also the super power to make OTHERS share a little insanity.
*** All of [=WoD=] had some kind of character that was completely out of its mind. Marauders, Black Spiral Dancers, Specters, [[HearingVoices every playable character in Hunter.]]
*** When the voices are real, are you still insane? But really, the Imbued of ''Hunter'' acquired more power the more they threw themselves into the Hunt, thus moving further away from humanity and its trappings (ethics, morals, emotions, etc), eventually turning into super-powered anti-supe fanatics who are human only in biological makeup.
*** And two of the creeds - the Hermits and Waywards - are broken right from the imbuing, since both get a direct pipeline to the PowersThatBe.
** True in ''TabletopGame/ChangelingTheLost'' for really great Power -- [[spoiler:sometime after reaching Wyrd 10]], they can lose all of their {{sanity|Meter}} in a matter of weeks. And it usually goes downhill [[TomatoInTheMirror from there.]]
** The Geniuses of the fan-game ''TabletopGame/GeniusTheTransgression''. [[MadScientist They're all mad]], [[IRejectYourReality and have the potential to get even madder]].
* The ''TabletopGame/ForgottenRealms'' setting has Sammaster, one of the mages "promoted" by Mystra to semidivine being status. This impaired his sanity, triggering a delusion (provoked by a [[DeusSexMachina ritual]]) that the goddess was infatuated with him, and the [[TreacherousAdvisor "friendly" advice]] of an evil priest [[FromBadToWorse made it even worse]]. He ended up stripped of power and convinced that dead dragons shall rule the world due to his bad translation of old prophecy. [[MoralEventHorizon To fulfill this prophecy]], he created dracoliches and the infamous [[AncientConspiracy Cult of the Dragon]].
* ''TabletopGame/BattleTech'' features several types of neural interface technology that can boost battlefield performance beyond what's possible with just the usual manual/voice controls and neurohelmet, but are correspondingly more invasive and dangerous. Clan [=ProtoMech=] pilots, who ''depend'' on this kind of interface to control their smaller-than-regular-'Mech war machines in the first place, consequently tend to become increasingly unstable over time and usually die young.
* This trope is one of the problems for magick-users in ''TabletopGame/UnknownArmies''. Adepts and avatars get their power by virtue of being so utterly obsessed with something (like drinking, or being the ultimate warrior) that it lets them alter reality. This means that most mages are a little nuts by necessity, and need to be pretty committed to their ideals if they want to become more powerful. It's no surprise that one of the big movers-and-shakers in the occult underground doesn't use magic at all.
* This is also popular in ''TabletopGame/{{Warhammer}}''. All magic is made from the powers of Chaos, and chaos likes to reshape things into {{Eldritch Abomination}}s. If a wizard uses too much juice, the side effects could range from his mind starts coming unhinged, to an explosion with a five mile radius. Being a worshiper of the Gods of Chaos also tends to do this, as their warriors are trying to earn enough glory to become daemon princes, but most end up getting killed or turned into Chaos Spawn long after they go completely insane. Skaven can be described as this, as their leaders tend to have a skewed view on things. Most Dark Elves could also count, especially with Malekeith.
* [[PsychicPowers Asyncs]] in ''TabletopGame/EclipsePhase'' are required to take one mental disorder for each level of the Psi trait they acquire because their powers come from a virus written by an alien entity that borders on EldritchAbomination. And unlike other disorders taken during character creation, they don't get extra character points for them.
* Pictured above, [[http://magiccards.info/cs/en/135.html Zur the Enchanter]] from ''TabletopGame/MagicTheGathering''. He was a powerful wizard who went mad trying to achieve immortality and attacked his former homeland Kjeldor. After his invasion was thwarted, he went into hiding and spent the rest of his days aloof from the world basking in his own power.
** This used to be the norm for planeswalkers, who once were basically gods. As pointed out by Jodah, their power and lack of need to see anyone else as being anything more than insects in comparison was strongly linked to their insanity. After the Mending, when planeswalkers just became people who can travel between dimensions, all the planeswalkers who saw themselves tripped from their power have either become power-hungry monsters or extremely morally dubious at best.
* This is a major function of ''TabletopGame/ArkhamHorror''. A number of powerful spells all require a sanity cost regardless of whether the spell successfully casts, and some spells, like "Dread Curse of Azazoth" give you an incredible +9 to combat checks. The downside is, with the wrong character, 2 sanity can be very hefty. Heck, even with a character that has a high sanity max like Harvey Walters, you could cast a spell like that and defeat an opponent, only for something like a Flying Polyp to reduce your sanity down to 1 just by showing up and you failing a horror check. As such, it's a risky attempt to use them, but sometimes you have little other option.
* The ''TabletopGame/DungeonsAndDragons'' 3rd Edition supplement ''Hero Builder's Guide'' has the Raver, a character build for Dwarven Sorcerers where they were driven insane by their magical powers manifesting. The Raver is described as being only kind of arcane spellcaster considered "acceptable" to Dwarves because they're obviously mentally ill and in need of help, but says that their families feel a guilty sense of relief if they decide to leave the delve.
[[/folder]]

[[folder:Live-Action TV]]
* ''Series/AgentsOfSHIELD'': In Season Five, [[JerkWithAHeartOfGold General]] [[TeethClenchedTeamwork Talbot]] infuses himself with [[GreenRocks gravitonium]] to save Coulson's team as a way of [[TheAtoner making amends]]. Jump a few episodes forward and he's gone from WellIntentionedExtremist who wants to power himself up to protect the Earth from [[Film/AvengersInfinityWar cosmic level threats]], to an AxCrazy DrunkOnTheDarkSide lunatic threatening to [[EarthShatteringKaboom crack the planet open like an egg]].
* ''Series/{{Angel}}'': Season three's "Birthday" depicts an alternate reality in which Cordelia never joined Angel Investigations. Doyle passed his visions on to Angel prior to his HeroicSacrifice, and Angel retreated into himself in his grief, with the visions only making things worse. Before long, Angel went completely insane from his own loneliness and his visions, to the extent that he would have visions of his victims. The worst of it all is that what Cordelia sees of that version of Angel, a babbling, incoherent mess who starts pounding his head on the wall while talking to her, is, according to that world's Wesley and Gunn, him on a good day.
* The 2000 ''Series/TheInvisibleMan'' series starring Vincent Ventresca had the invisibility caused by a synthetic gland that excreted a light-bending substance, a secondary side effect of which (after a long enough period of time) was insanity, until the counteragent was administered - though this was only a plot focus once or twice. The ''primary'' side-effects were unpleasant enough that the invisible man usually got the counteragent before the secondary side-effects kicked in. This was due to sabotage on the part of one of the creators of the gland. He intended to use the counteragent to control whoever possessed the gland. Given that they explain Quicksilver Madness as being related to frontal lobe dysfunction, and the frontal lobes are involved in suppressing impulses, the main character presumably ''wants'' to be violent but is controlling himself. If they'd done the procedure on someone else, he'd probably have just had AttentionDeficitOohShiny. The main character refers to this condition several times as "the walking [[AllPsychologyIsFreudian id]]".
* ''Series/StargateSG1'':
** This trope is applied to partly explain the evil megalomania of the show's main enemies, the Goa'uld: it's a side effect of revitalizing themselves with their all-healing sarcophagi too many times. When in "Absolute Power" Daniel Jackson asks to be given just a small portion of knowledge from the Goa'uld's ancestral memories, he is quickly shown that that would make him go wonky too. (See also YouAreNotReady.)
** In an interesting twist, when O'Neill is exposed to "good" knowledge (twice), he also swiftly suffers mental breakdown; no evil megalomania, but his brain begins to fail from the strain of holding on to it all.
** There's also the armband episode, in which O'Neill, Jackson, and Carter get [[AppliedPhlebotinum magic jewelry]] that makes them super-strong and fast. It's downplayed in that the "craziest" they ever get is impulsive and overconfident.
* River Tam from ''Series/{{Firefly}}''. See ''Film/{{Serenity}}'' reference above, as the extent of her abilities is only hinted at until the movie. She's still crazy in both, though.
* Spoofed rather effectively on ''Series/ThatMitchellAndWebbLook'', with a sketch involving a man going insane with his power to levitate...''biscuits''.
* In ''Series/{{Supernatural}}'', most of the people who are shown to have developed PsychicPowers like Sam go [[FaceHeelTurn off the deep end]]. Doesn't help that they're [[TykeBomb designed with this in mind]]: [[spoiler:When they go evil, they gain complete control over their powers, which makes it ''much'' easier for them to kill the sane ones]].
** At the end of season six, after JumpingOffTheSlipperySlope, [[spoiler:Castiel boosts his powers with the millions of souls from purgatory, [[AGodAmI names himself the new God]], and demands the boys bow down or be destroyed. ''Then'' he commences with the [[DisproportionateRetribution smiting]]]].
** It seems to be a running thing with powerful angels in the show. The more power you have, the less you care about humans and see mankind as tiny ants to be stepped on (because the gap in power is so great). The Archangels for one, who are most powerful of all: Michael, Lucifer and Raphael are all heartless dicks, and Castiel became one after gaining so much power. Anyone else see a pattern here? (Yes, I'm pretty much ignoring Gabriel. But the guy spent ''decades'' on earth and had plenty of time to warm up to humans, unlike his three older brothers. And Castiel, who already liked humans despite the short time he spent on earth (compared to Gabriel), must have felt so high on Purgatory souls it screwed up with his mind.)
* An episode of ''Series/{{Farscape}}'' had the crew getting their hands on a powerful weapon that attached itself to the user, powered by an addictive drug with all the properties of TV steroids, which they needed to use to get Rygel back. Predictably, D'Argo, Aeryn, and Crichton all had to use it at some point. Thankfully, it had a built-in off switch -- if the wearer lost consciousness, the weapon detached itself.
* ''Series/{{Heroes}}'' has Sylar, who went from a bookish watchmaker to a psychopathic serial killer after he began to acquire superpowers. Gaining those powers involves killing people and stealing their brains, so it's kind of a chicken-or-the-egg matter with him.
** Season 3 episode 4 shows that [[spoiler:his original power was what made him go crazy. When Peter mimics this power, the first thing he does with it (well, the first thing after figuring out how to fix the Sylar watch) is to "figure out" what President Nathan Petrelli is up to... so he cuts open his skull]]. As of Season 3 episode 24 (second to last episode of Volume 4) Sylar's latest power acquisition of [[spoiler:physical shapeshifting by absorbing other people's DNA]] combined with [[spoiler:psychometry, the ability to touch objects or people and "read" their history by picking up emotions and visions of past scenes]] has finally driven him completely bonkers, full blown [[EvenBadMenLoveTheirMamas Norman Bates-style crazy]]. It takes a lot to creep out ''Sylar'', but he finally managed to do it to himself.
** The leader of [[AncientConspiracy The Company]] claims that mental illness is a side effect of the mind trying to cope with possessing superpowers, but it's likely he was simply lying to convince Niki to work for him. Plus, HRG says after they capture Sylar that all the changes to his DNA have made Sylar more and more insane.
** Mohinder became more aggressive and developed a compulsion to abduct people and store them in cocoons after injecting himself with his SuperSerum.
** Subverted pretty well in Season 3 with Scott, the Marine chosen to get the super soldier injection (a variant of the same serum referenced above with Mohinder). After he finishes twitching and panting, Scott glares at his benefactors, demonstrates his new super strength by throwing a chair hard enough to embed it into the wall... then smiles and nonchalantly remarks that he feels good. He spends his brief remaining screen time behaving quite sensibly until Knox sneaks up behind him and 360's his head.
** Volume Five BigBad Samuel Sullivan has been revealed to be this way. [[spoiler:His power level is directly proportional to how many evolved humans are present. The more supers are around him, the more powerful he becomes. He's even been described as an ego-maniac who doesn't hold the lives of the normal folk as having any worth, and he'll happily off anyone who stands in his way or hurts any member of his "family."]]
* In the third season of ''Series/{{Roswell}}'', Michael the sidekick ends up [[spoiler:becoming the back-up king after the real king's (temporary) death]] and promptly goes crazy and [[spoiler: tries to kill his supposedly-destined wife's human husband]].
* One of the oldest TV examples of this trope is the ''Series/StarTrekTheOriginalSeries'' episode "Where No Man Has Gone Before". As Gary Mitchell's god-like psionic powers increase, he becomes a callous megalomaniac, complete with GlowingEyesOfDoom. Dr. Elizabeth Dehner was able to restrain herself long enough to do a HeroicSacrifice, perhaps because her training as a psychiatrist made her better able to psychoanalyze herself.
* In the first series ''Series/StarTrekTheNextGeneration'' episode "Hide and Q", the focus of the story is Riker's temptation with omnipotence, and how unlimited power takes away his self control and humanity, but fortunately Captain Picard helps him overcome the temptation to save lives and prevent natural disasters. Oh, he uses them to get rid of the space monkeys, so they didn't go to waste.
** A more subtle example in "Tin Man": A Betazoid whose telepathic abilities manifested shortly after birth, and are much stronger than normal, instead of at puberty as is normal. He's not crazy, just poorly adjusted and extremely stressed out. Humanoids stress him so badly that he's been hospitalized repeatedly for it. The nature of his telepathic abilities is such that he gets everything about a person immediately, leading to him treasuring the time he got to spend with Data, ''the only person he ever got to know like a normal person would''.
* ''Series/StarTrekEnterprise''. In the MirrorUniverse episode, Mirror Archer gets his hands on a Constitution-class heavy cruiser a hundred years in advance of his own. At first he just wants to get credit for its seizure, and end a rebellion against the Terran Empire, but as he realises the power he's got, Mirror Archer becomes more paranoid and power-hungry, eventually deciding to take over the Terran Empire.
-->'''Mirror T'Pol:''' You heard the captain. He's delusional!
-->'''Mirror Phlox:''' It's not a delusion if the captain has the power to do what he says. And [[CurbStompBattle from what I've seen]] he certainly does.
* In ''Series/{{Millennium}}'', Frank and Laura's unique perceptions of reality lead to mental breakdowns. [[spoiler:Frank initially seems to have recovered from his; by the third season, however, he's again fraying at the edges.]]
* In the 2007 remake of the ''Series/BionicWoman'', Sarah Corvus, Bionic Woman 1.0, goes crazy after getting her power.
* A lot of the meteor freaks in ''{{Series/Smallville}}'' end up going insane and evil. Granted, some of the characters already have a screw (or several) loose before becoming meteor freaks (e.g. [[PsychoLesbian Tina Greer]], Greg Arkin), but some only went nuts after getting powers. Sean Kelvin for example -- before getting powers he was just a jerk, after he got powers he became a SerialKiller. Even the non-killing meteor freaks aren't always all right in the head (e.g. Cyrus Krupp). Also, when normal people get [[PhysicalGod Kryptonian]] powers, [[AGodAmI they tend to go nuts]] (e.g. Jeremiah Holdsclaw, Lana Lang, Eric Summers). Not ''all'' meteor freaks and normal-humans-with-Kryptonian-powers go nuts ([[spoiler:[[EmpathicHealer Chloe Sullivan]]]] for the meteor freaks, [[MuggleFosterParents Jonathan Kent]] and Comicbook/LoisLane for the humans-with-Kryptonian-powers), just most of them.
* In ''Series/TheGreatestAmericanHero'', Ralph (who lost the manual to his supersuit) meets a filthy rich old man who ''kept'' his manual and knew everything the suit could do. The guy used his suit to become rich and crush his enemies like bugs, and the aliens finally took the suit away. The old man thinks it's a good thing Ralph doesn't have the manual. At the end of the story, the old man gives the Lord Acton page quote and says, "I wonder if he had a suit too."
* A major plot arc in ''Series/BabylonFive'' that was mostly abandoned (but still hinted at) with Andrea Thompson's departure was the Psi Corps' attempt to solve the frequent insanity that accompanied telekinetic powers.
* ''Series/DoctorWho'':
** In "[[Recap/DoctorWhoS30E13JourneysEnd Journey's End]]", the Doctor's companion, Donna Noble, [[spoiler:somehow gains every bit of knowledge and power that the Doctor has.]] The Doctor, unfortunately, is forced to give Donna a complete mind wipe of her entire knowledge of the Doctor/the TARDIS/the entire time she was on the show because [[spoiler:being ''the Doctor Donna'', as the Ood called her,]] will kill her. This circumstance means that the Doctor can never see Donna again, as she will remember everything and die. It's not going insane with power that would kill her, it's that humans are physically unequipped to handle a Time Lord mind. Donna was still physically human but with a Time Lord consciousness, and it was going to literally burn her brain out in very short order, certainly before she had time to go mad with power.
** A better example would be the Doctor himself. Despite having, essentially, the power of a god, he mostly averts this trope. Except [[Recap/DoctorWhoS30E16TheWatersOfMars that one time when he was pushed a bit too far]], lost it spectacularly, and became, briefly, an example of this trope.
** An even better example is [[GreaterScopeVillain Rassilon]] in The End of Time, who is willing to [[OmnicidalManiac destroy all of time and space]] to win the war against the Daleks.
** Subverted with Davros, who was always completely insane, and gaining great power only gave him more opportunities to carry out his insane plans.
* In ''Series/TheSixMillionDollarMan'', Steve Austin adapted to his bionic replacements very well, remaining well-integrated and with his reasonably decent moral sense intact. Not everyone else who was given/forced to take bionics did as well. Jaimee Summers was plagued with amnesia and mental troubles, and another bionic man went the "crazy with power" route as well. The implication was that power didn't necessarily go with madness... but it easily could.
* ''Series/BuffyTheVampireSlayer'':
** In the episode "Earshot," Buffy is contaminated by a telepathic demon. This has only happened to one other person, and it caused him to go insane and live as a hermit. Buffy is heading the same way when the Scoobies undo the effects.
** Willow is apparently the most powerful witch in the world. By a lot. But she's also very vulnerable to going DrunkOnTheDarkSide, to the point that she once came within seconds of wiping out all life on Earth.
* This is a recurring theme in the series ''Film/BlackScorpion''. If any character gains a {{Power}} from an accident, then [[EvilLaugh insane laughter]] is sure to follow.
* ''Series/{{Charmed|1998}}'':
** Any human who gains a power. They will be unable to handle it and eventually turn demonically insane.
** Those who gain Empathy when they weren't supposed to (especially for demons who cannot handle emotion).
** A group of demons who ''purposely'' put powers into humans to drive them insane and wreck their lives exist. One such victim received the power to spray acid from her hands. [[spoiler:Cole uses this on Paige to tip her over the edge and perform magically evil acts in front of her, thereby making her accusations less credible in the eyes of everyone else.]]
* Rufus Zeno from ''Series/HouseOfAnubis'' was actually the protector of Sarah Frobisher-Smythe, TheChosenOne before Nina came along, but he was corrupted by his power, making him crazy and hungry for more power.
* PlayedForLaughs in an episode of ''Series/WouldILieToYou'' where regular team captain Lee Mack was unable to attend the recording and Greg Davies stood in for him. When Davies decided to overrule both his teammates and say a story was a lie even though they both thought it was true, everyone acted as if he had gone mad with power. (The story ''was'' true.)
-->'''David Mitchell:''' That's a very, very irresponsible use of power!\\
'''Greg:''' Yeah, well, Lee Mack's not here, this is my bench, and I tell you it's a lie!\\
'''Rob Brydon:''' Why? What about that was unconvincing?\\
'''Greg:''' It's irrelevant, I've made my decision!
[[/folder]]

[[folder:Literature]]
* Magic users in ''Literature/TheDawnhounds'' have a form of ResurrectiveImmortality that means [[EldritchAbomination their patrons]] throw them back whenever they die. Each resurrection makes them more powerful, but also chips away at their sanity and personhood. It's implied that—after enough resurrections—they lose their grip on reality entirely and [[EldritchAbomination ascend out of the world.]]
* Poison-users in ''Literature/DisAcedia'' eventually go insane, including [[spoiler: the main character himself]].
* A key element of Literature/TheReckonersTrilogy. [[DifferentlyPoweredIndividual Epics]] started getting powers about 10 years before the first novel, and all end up falling somewhere between minor sociopaths to evil dictators. The series focuses on normal humans trying to kill powerful epics with their weaknesses, as well as learning more about the origin of Epic powers and why everyone with them seems to be insane. [[spoiler: It turns out that with the exception of Transference Epics (aka Gifters) who give their powers away, any Epic who uses their powers will turn into a hateful, angry sociopath in minutes. Even people in close proximity are not immune to this -- it's implied that Epic powers, even when Gifted, have a high probability of causing the same arrogant amorality in other people when used by them instead. One character alludes to a time when the police of his hometown [[LesCollaborateurs joined with an Epic]] and "The good ones [left the force.] The bad ones stayed on, and they got worse." The main character, David, eventually discovers that the being who is secretly gifting Epic power is also what's causing them to turn people evil.]]
* In the ''Literature/HeroDotCom'' series, along with its sister series [[https://tvtropes.org/pmwiki/pmwiki.php/Literature/VillainDotNet ''Villain Dot Net'']], when a Prime, someone born with powers that doesn't need to download them from the titular websites, downloads powers from them, it either causes insanity or death.
** There are also the six [[MetaOrigin Core Powers]], the ''original'' powers from which ''every other power in existence'' is only a weakened, mutated descendant of one or more of these powers, which can only be wielded by one person at a time (though 2 of them were divided into segments that different people could use at once, albeit in a weakened form). Of the six, 3 are known, a TimeMaster power, wielded by the villainous Lord Eon, power over life and death, and a GravityMaster power. The Core Powers can corrupt anyone without the strength of will to resist the lure of their sheer power, with only a few characters being immune.
* ''Literature/TheNightAngelTrilogy'' by Brent Weeks: Dorian is one of the more powerful magicians in the book. He is immensely powerful in both the normal talent and the more addictive [[BlackMagic vir]], and is said to be the best healer in living memory [[spoiler:([[ReallySevenHundredYearsOld living memory is a vague expression]])]]. But it is his prophetic gift that really gets to him. By the end, [[spoiler:he is just [[TroubledFetalPosition sitting in a corner, laughing]]]].
* ''Literature/TheIronTeeth'': After his transformation Blacknail couldn't control his thoughts, and attacked Saeter. Only long training helped him. Still, the beast inside him is powerful and biding its time.
* ''Saidin'', the magic used by males in ''Literature/TheWheelOfTime'', is tainted by The Dark One, causing inevitable insanity in its users. As time progresses, one of the main characters begins to show the effects of this, becoming schizophrenic, moody, and temperamental; halfway through the series, he seems like a completely different person, though he ''is'' [[TheChosenOne under a lot of pressure]]... The Forsaken also have access to what they call the True Power, an extremely addictive, ''evil'' flavor of magic that also has serious psychological consequences; most would only consider using it under ''dire'' need.
** Possibly exemplified best when some poor soul using ''Saidin'' breaks down ''AFTER ONE DAY,'' and starts screaming that there are spiders under his skin.
** It's also worth mentioning that ''Saidin'' use can bring about other lovely effects, such as rotting flesh. It is entirely random as to which will affect you first, when, and to what degree.
* Creator/BrandonSanderson's ''Franchise/{{Mistborn}}'' series:
** Played straight and later justified in the third book with the Lord Ruler, a main villain.
** Also true for the Lord Ruler's [[TheDragon Dragons]], the Steel Inquisitors. The Inquisitors use [[spoiler:hemalurgy, a ghoulish form of magic that allows them to remove portions of someone else's lifeforce by killing them with a metal spike, trapping said life force in the spike, and then impaling *themselves* with said spike to acquire whatever power they stole]]. This makes them supremely powerful, but is in no way good for their long-term mental health. All the Inquisitors we see in the series are somewhat... [[AxCrazy homicidal]].
*** It doesn't help that [[spoiler:hemalurgy]] provides an "in" for [[spoiler:the series' BigBad, the God of death and destruction called Ruin, to mess around with people's minds and in the case of people with several spikes like Inquisitors', outright control them]].
* ''Literature/SoonIWillBeInvincible'', which even gives it a medical name: "Malign Hypercognition Disorder".
* The [[ArtifactOfDoom One Ring]] in ''Literature/TheLordOfTheRings'' slowly destroys the sanity of whatever schmuck has got a hold of it, first by making them obsessed with it and unable to let it come to harm, then tormenting and tempting them with visions of power they probably can't achieve, and finally devouring their mind. The other Nine Rings wrecked their bearers as well, giving them AgeWithoutYouth until every moment of existence is an unbearable torture, and making them unable to disobey Sauron's commands even for an instant. The Seven probably aren't very safe either, though Dwarves seem to be mostly immune to the effects. Really, only the Three (which Sauron never touched) aren't liable to drive a wielder crazy, and that's only unless/until he regains the Ruling Ring.
* [[Franchise/StarWars Sith philosophy]] encourages not controlling one's emotions, so this trope happens a lot. For specific examples:
** Jacen Solo in the "Literature/LegacyOfTheForce" novels seems to get crazier and crazier the more he falls to the Dark Side of the Force. He first justifies his actions as necessary sacrifices for the good of the galaxy, but by the end of "Fury," [[spoiler:he uses the Force to break an underling's neck for failing him]]. They don't call it TheDarkSide for no reason. The same applies to Anakin/Vader and a host of other ExpandedUniverse characters.
* In Creator/DavidBrin's original novel ''Literature/ThePostman'', the brutal survivalists/Holnists are led by General Macklin and his aides, who were pre-war experiments on creating soldiers with superhuman strength and speed. The government chose the most ruthless, intelligent, and efficient killers in its military, with foreseeable results when the US itself turned into an anarchistic warzone. Macklin is finally killed by George Powhatan, a later experiment of the same ilk, though with a nature loving Neo-Hippie as subject.
* ''Midnight'' by Creator/DeanKoontz. A [[MadScientist rather twisted]] [[StrawVulcan scientific genius]] has designed microchip-like spheres that augment a person's mental and physical abilities, but suppress all their emotions except fear, which produces some rather odd behavior on its own. Then the townspeople begin to discover that an accidental side-effect gives them mind-over-matter shapeshifting powers, and they promptly escape into forms in which their lack of emotions doesn't bother them -- either animalistic creatures without the intelligence to notice, or cyborgs without any emotion at all. Everyone dies.
* In Creator/HGWells's ''Literature/TheInvisibleMan'', the titular character started out as a psychopath, but it gets much worse after he discovers the ability to turn himself invisible.
* ''Literature/EvieScelan'': At the very least, most mages in the novels are highly paranoid. The title character aggressively cultivates a normal life to keep from going crazy herself.
* Creator/TimothyZahn's ''[[Literature/TheCobraTrilogy Cobra Trilogy]]'' has people being made into Super Soldiers and adjusting to new strength and speed and lasers in a matter of weeks. They're carefully screened beforehand; only the most emotionally stable ones actually become [[FunWithAcronyms Cobras]]. Even so, a percent of them do not handle the transition well and develop something called a "Titan complex", the belief that one is so powerful that one is above normal laws and standards. Handing someone all that physical power at once, instead of having to acquire and use it in small increments, essentially sidesteps the usual adjustment mechanisms, according to the books. These people tend to decide that they know what's best and proceed to rebel until other Cobras either kill them or restrain them long enough to have the Super part downgraded. A major plot point is the main character, a Cobra himself, realizing that he has to help his colonies secede from the Dominion of Man and trying not to look like he's developed the complex.
* Creator/AnthonyBurgess' ''One Hand Clapping'' is about a man with hyper-photographic memory, who uses this ability to become rich, and show his wife the life she deserves. She later finds out not being able to forget things has driven him insane, when he reveals his plan all along; to show her the good life, before ending both their lives in a suicide pact.
* In ''The Alchymist'', one who goes the quick way to being "awakened" will not be able to comprehend the power, resulting in death.
* In ''Literature/TheCycleOfFire'', the process of mastering fire powers involves experiencing being burnt alive. The trainee must get past the pain to understand the flames, which usually requires sacrificing all capacity for empathy, making them a sociopath.
* In the Creator/DaleBrown book ''Warrior Class'', Fursenko suspects that Yegorov is suffering from this, the power conferred on him by the [[CoolPlane Fisikous/Metyor-179]] turning him from a mild-mannered and intelligent person to a seemingly AxCrazy BloodKnight.
* Creator/MeganLindholm's ''Literature/WizardOfThePigeons'' is based on a radical re-interpretation of this trope. Magic usually comes hand in hand with [[LossOfIdentity letting go of your previous life, memories, and basic perception of reality]]. Usually, the mage is so divorced from the outside world that he or she cannot hold down a job or personal relationship, and usually ends up living on the street. They also have to follow [[SuperOCD their own set of arbitrary rules and rituals]], implicitly for the PlacebotinumEffect. Cassie has been doing this since the Trojan War, and [[CrazyAwesome is so uninhibited by her environment that she can bend reality to her whim.]]
* Creator/MichaelSwanwick's short story "The Promise of God" is based on the premise that using magic gradually erodes a magician's moral sense until they no longer have any concept of right and wrong; magicians are kept in check by being assigned guardians whom they are trained to obey without question.
* ''Literature/MyWorkIsNotYetDone'' by Creator/ThomasLigotti: [[ZigZaggingTrope Zig-Zagged]] by Frank Dominio, the AntiHero narrator of the short novel, who manages to [[WoobieDestroyerOfWorlds go violently insane]] ''before'' he makes his FromNobodyToNightmare transition, then proceed to ''[[UpToEleven lose it even more]]'' whilst simultaneously gaining more and more control of his extremely [[RealityWarper scary]] [[LovecraftianSuperpower superpowers]].
* ''Ren Dhark'': Inverted in one issue of this German SF series. At one point, the Terran world government decides to start a secret cyborg project with the help of a brilliant and highly ethical scientist. Thanks to very thorough advance evaluation and screening, the actual ''cyborgs'' turn out fine and become recurring supporting characters later on; instead, it's a candidate who gets ''turned down'' in the end (ironically precisely because he failed one of the psychological test scenarios) who goes a little AxCrazy as a result, devises a plan to destroy the entire fledgling institute, and almost succeeds.
* In the ''Literature/KeysToTheKingdom'' series, Arthur begins to slowly get driven insane the more Keys he gets, and almost uses the power of the Keys to kill Denizens several times, but luckily manages to stop himself before he ever does.
* ''Literature/TwentyThousandLeaguesUnderTheSea'' subtly shows how Captain Nemo is slowly but surely losing his sanity by using the [[ArtifactOfDoom Nautilus]] as a WeaponOfMassDestruction: At the state of technology in 1869, a submarine could easily destroy any ship afloat without possibility of retaliation, so Nemo could ''easily'' cross the MoralEventHorizon once and again.
* ''Literature/HeartOfDarkness'' critiques Britain's "liberal imperialism" in the form of Kurtz who went insane because he has absolute power with no one to stop him.
* In Kelley Armstrong's ''[[Literature/TheOtherworld Women of the Otherworld]]'' series, this happens to [[BlessedWithSuck necromancers and clairvoyants]] over time, and the more powerful they are, the faster their mental state degrades. Interestingly, necromancers can stave off the madness longer by ''using'' their powers rather than suppressing them.
--> Good necromancers are plagued by demanding spirits. They're taught how to erect the mental ramparts but, over time, the cracks begin to show, and the best necromancers almost invariably are driven mad by late middle age. To maintain their sanity for as long as possible they must regularly relieve the pressure by lowering the gate and communicating with the spirit world. ... Clairvoyants also live with constant encroachments on their mental barricades, images and visions of other lives. When they lower the gate, though, it doesn't quite close properly, and gapes a little more each time.[[note]]-- Kelley Armstrong, ''Industrial Magic''[[/note]]
* From ''Literature/{{Animorphs}}'', we have the BigBad, Visser Three. In the main books, he's a GeneralFailure with a strategy of brute force that's completely unsuited to the campaign of stealthy infiltration he's waging. Later, the prequel Chronicles books showed the younger Visser as a very capable ManipulativeBastard, exhibiting a thoughtfulness and cunning completely absent from his main incarnation. It becomes quite clear that once Esplin achieved his goal of becoming the only Andalite-Controller in the universe he let the power go to his "head" (it didn't help that his new host was a disgraced and mentally unstable ex-GeneralRipper either). It was all downhill for him from there.
** To a certain degree ''all'' Yeerks have the potential to succumb to this, as they are a PuppeteerParasite race who incorporate elements of the FusionDance trope into their GrandTheftMe lifestyle. Literally ''every'' Yeerk character in the series is shown as taking on aspects of their host -- Aftran in #19 has a somewhat childish attitude and mannerisms as her host is an actual child, the TV personality Yeerk in #35 has a bombastic LargeHam persona, and so on. The biggest smoking gun for this, though, is Visser Three's [[TheDragon Dragon]] Taylor, a character who manages the ''very'' impressive feat of out-crazying her boss due to taking a severely traumatized and narcissistic teenager for her host while not being entirely mentally stable herself.
** The morphing ability used by the heroes is also a form of this, as every time they morph an animal they are interfaced with that animal's instincts. While certain animals have very mild instincts that are easily controlled, certain other animals are much harder to control (in the most extreme case, the kids almost lose their sentience entirely when morphing ants). It's not very predictable, either, even after they turn the learning curve and develop a greater understanding of morphing's rules and limits.
* In ''Literature/{{gone}}'', every villain (sans Zil) has awesome powers, and most of them are at some point insane from the revelation.
* ''Literature/PocketInTheSea'': Lillenthal has shades of this in his character, but it's not clear if this is deliberate obtusification or genuine mental deterioration from living with a telepathic ability.
* Seems to be a side effect of becoming a [[spoiler:hoshek]] in ''Literature/TheQuestOfTheUnaligned'', as infusing your soul with the fundamental essence of evil is not good for the mind.
** A lesser form of this effect seems to occur to Ruahkini. None too level-headed to begin with, becoming the second-most-powerful [[BlowYouAway ruahk]] in the world infused him with a double portion of wind magic's flightiness and absent-mindedness.
* A core premise for ''Literature/GloryInTheThunder''. Holding an Aspect greatly taxes mental fortitude, and gods are known for being more likely to go mad the longer they live. This means the immortals in particular tend to have left sanity behind a long time ago.
* A common trope in ''Literature/TheDresdenFiles'', such as [[OurWerewolvesAreDifferent Hexenwulfen belts]], the coins of the [[FallenAngel Order Of The Blackened Denarians]], and the mantle of the [[TheFairFolk Winter Knight]]. [[spoiler:As Harry finds out firsthand.]]
* The Parshendi "forms of power" in ''Literature/TheStormlightArchive'' involve bonding with a sliver of the Platonic ideal of hatred. Not the best thing for one's mind. The strongest of these, 'The Fused', are affected badly enough that any who retain some sanity are considered qualified for leadership positions by default.
* ''Literature/TheNightsDawnTrilogy'': Dexter Quinn is a magnificent example, [[spoiler:taking back his own body from possession and using those powers to try to annihilate Earth]].
* In ''Literature/VampireAcademy'', all Moroi spirit users are affected mentally by spirit-use, as it is drawn from themselves (as opposed to an element, such as air). And the more they use it, the worse it gets. It manifests itself differently in each individual: Lissa becomes extremely depressed at one point, which causes her cutting, Adrian has bipolar disorder, and Sonya Karp dealt with her insanity by turning Strigoi -- although now that [[spoiler:she's turned back, she seems to be okay, despite using spirit in most of her free time to find a Strigoi vaccine]].
* ''Literature/AFireUponTheDeep'' by Creator/VernorVinge has "godshatter", the NeuralImplanting by {{Sufficiently Advanced Alien}}s of a massive ExpositionBeam into a person's brain. It would probably be super helpful if the [[BlessedWithSuck seemingly random jumble of information]] didn't turn the person into an erratic, drooling savant for most of the time.
* The ''Literature/ParadoxTrilogy'' has a couple of examples. Maat, a powerful psychic, is said to have been driven mad by channeling more plasmex than any human was meant to contain. Symbionts are also prone to this, suffering mental instability as the price of the implants which grant them superhuman strength.
* ''Literature/JourneyToChaos'': Breathing in the magical mist known as "Fog" will give the user tremendous boosts to both magical and physical abilities. It will also give them one heck of a PowerHigh and then send them over the deep end into the monster mentality known as "Monsanity".
* In ''Literature/MaledictionTrilogy'' many pure-blooded trolls can use very powerful magic and are also mentally unstable - probably due to 500 years of excessive inbreeding. The best example is young troll prince Roland, who is extremely powerful (like everyone in his family) and stark raving mad. His favourite pastime is to go out in the streets and brutally kill random mixed-blood trolls (who in this society are slaves without any rights).
* In Creator/JoeHaldeman's epistolary short story [[http://www.lightspeedmagazine.com/fiction/more-than-the-sum-of-his-parts/ "More Than the Sum of His Parts,"]] a lunar construction worker has half his body burned away when he gets caught in a jet of aluminum vapor, and undergoes massive reconstructive surgery, including robotic limbs and a prosthetic penis. Naturally he gets completely drunk with the power and capability of his new extremities. HilarityEnsues.
* The title character in ''Literature/EdenGreen'' is a rationalist and amateur biologist, but once infected with an alien needle symbiote, its immortality (and increasing power) gradually push her toward the deep end.
* ''Literature/TheInfected'': The Infected gain superpowers but also a "first mode" or sort of personalized mental disorder. Some are existing disorders but worse and untreatable, several are emotional states amped up, like a man who can actually never stop being happy, or a person with crippling social anxiety.
* In ''Literature/AllOurYesterdays'', future James started out wanting to use time travel to help people and save them, but he grew so far gone that he turned America into a police state and [[spoiler:sent someone back in time to kill his own brother]].
* In ''Literature/{{Discworld}}'', witches make a study of {{def|iedTrope}}ying this. The combination of magical power, a keen (and [[ManipulativeBastard sometimes bruising]]) grasp of human psychology, and a solitary lifestyle tend to do weird things to their minds over time; so they take care to keep each other grounded and at least somewhat socially engaged so they don't "start cackling."
* In ''Literature/PleaseDontTellMyParentsYouBelieveHer'', Penny [[spoiler:(the "Meatbag" one)]] has figured out a way to invoke her powers on command through an ingested drug. However, it's making her progressively more violent and insane. And it's addictive.
* ''Literature/TheSisterVerseAndTheTalonsOfRuin'' has this in the powers granted by [[EldritchAbomination the Lord in White]]. All the characters in the first act completely lose their minds, and any darklings encountered are all wildly unstable.
* In ''Literature/{{Touch}},'' part of the backstory involves Earth's mages having to work together to stop an EldritchAbomination. Part of the solution involved everyone with SuperEmpowering abilities touching one guy who faced the thing in the final battle. He won, but he's ''not well,'' physically or mentally. His last coherent words were screaming for his mother, and he's visited daily by someone with ForcedSleep powers.
* ''Literature/SchooledInMagic'': Necromancers all eventually go mad with the amount of power they acquire from human sacrifice. [[spoiler: The mechanics are revealed over the course of the books and fully explained in ''Past Tense''. It's not necromancy itself, but too much mana for the human brain to handle, and the necromantic rite in particular fries the user's brain like an egg from the amount of power drawn. In the past, ''all'' magicians eventually went mad from channeling too much uncontrolled power, before the introduction of proper spellwork techniques.]]
* In ''Literature/NineGoblins'', all powerful wizards are certifiably insane. Keeping a firm grip on reality seems to check out when the ability to warp reality to your whim checks in.
[[/folder]]

[[folder:Films -- Animation]]
* Titan in ''WesternAnimation/{{Megamind}}'' mixes this with great immaturity. Hal is a feckless, mildly stalker-ish manchild with a creepy crush on Roxanne. Normally, he's completely harmless. But once he gets powers, that instability creates a complete psycho.
* The villains of the ''WesternAnimation/MyLittlePonyEquestriaGirls'' series of movies tend to go psycho when toying with power that they don't understand. They also tend to get [[EvilIsHammy much more hammy]].
** Sunset Shimmer in [[WesternAnimation/MyLittlePonyEquestriaGirls1 the first move]]. After putting on the Element of Magic, she undergoes a PainfulTransformation into a demon, and promptly [[JumpingOffTheSlipperySlope jumps off the slippery slope]], with her goal changing from "get Princess Celestia to acknowledge me" to "conquer Equestria with my brainwashed army". Notably, when she's taken down and reverts to human form, she's ''crying'' in horror about the things she did.
** In ''WesternAnimation/MyLittlePonyEquestriaGirlsFriendshipGames'', [[spoiler:Human Twilight is pressured by Principal Cinch and the others into unleashing the magic from her device to help Crystal Prep win the games, which contains all the captured magic from the Mane Six over the course of the movie. The intense exposure causes her to snap and transform into a evil magical winged demon form called [[SuperpoweredEvilSide Midnight Sparkle]], DrunkWithPower and dead set on opening dangerous portals to Equestria in order to understand magic, at the expense of destroying their world. It takes the combined efforts of Spike and Sunset Shimmer to snap her out of it]].
** In ''WesternAnimation/MyLittlePonyEquestriaGirlsLegendOfEverfree'', Gaea Everfree is the result of someone going through this. [[spoiler:It turns out to be Gloriosa Daisy, who had been using some of the magical ability in small crystals to [[GreenThumb control plant life]]. When Gloriosa goes from using some of the magic to all of it, she transforms into a monstrous version of herself, surrounding the entire camp with thorns [[AntiVillain to prevent the camp from being taken over by Filthy Rich]]]].
** ''WesternAnimation/MyLittlePonyEquestriaGirlsMagicalMovieNight'' has [[spoiler:Juniper Montage]] who in the third episode finds a magic mirror that shows her what she desires (to be an adored movie star). After using the mirror to grant her wishes and sucking the main cast inside, the mirror powers up and turns her into a giant version of her movie star self, as well as giving her delusions that the people running and fleeing in terror are all actually just admiring fans. The quick down-slide in her sanity from the second episode (where she just sabotaged a movie) is blamed on the mirror and she is EasilyForgiven, with references to Twilight and Sunset's instances of the trope from above being used as justification.
* As the page quote shows, [[Creator/AlbertBrooks Russ Cargill]], head of the Environmental Protection Agency in ''WesternAnimation/TheSimpsonsMovie'', quickly loses it. What starts as [[DomedHometown sealing away Springfield]] [[QuarantineWithExtremePrejudice to keep an environmental disaster]] from spreading leads to preventing anyone from escaping the city, roaming death squads, and ultimately [[spoiler: trying to destroy Springfield altogether]].
[[/folder]]

[[folder:Films -- Live-Action]]
* ''Film/{{Bananas}}'': After overthrowing the government of San Marcos, rebel leader Esposito declares himself the new president. Esposito also announces "the official language of San Marcos will be Swedish", "citizens will be required to change their underwear every half-hour", and "all children under 16 years old are now 16 years old." He spends the remainder of the film in an insane asylum.
* Jean Grey in her manifestation as Dark Phoenix in ''Film/XMenTheLastStand''. Although it is explained that she was already mentally unstable as a girl and her massive powers had to be reduced for her own good and that of everyone around her by putting mental blocks into her psyche. When these were removed, she started killing people with her mind. [[note]](This is actually closer to the original Phoenix story than the later comic and adaptation stories that portray Jean as having been TouchedByVorlons; see the Comic Books section above.)[[/note]]
* In ''Film/RoboCop2'', the evil corporation OCP attempts to build a successor to [=RoboCop=], but in all cases the new cyborg goes crazy and commits suicide. Finally, they stick the brain of a convicted, drug-addicted, psychopath into the cyborg. That doesn't work out too well in the end, either. Ironically, the scientists theorize that [=RoboCop=] was a success due to the very qualities that made Murphy a good cop in life: his highly Catholic upbringing and stable family life imbued him with a strong moral compass, selfless devotion to duty, and an [[ICannotSelfTerminate aversion to suicide]]. Then they turn around and choose a murderous psychopath, because they thought that they could control him through his drug addiction. Umm... Nope. Their reasoning was that just as a selfless cop would not kill himself, a sociopath would desire the power and immortality that comes with being an indestructible cyborg. While this is true, [[IdiotBall nobody seemed to catch onto the fact that a RoboCop also needed to be dedicated to duty rather than, say, murdering everybody to get a fix]]. Not only would a sociopathic criminal not care about duty, they also didn't see fit to hardcode directives into it like they did with the original.
* ''Film/ForbiddenPlanet'' exhibits this principle most chillingly through Morbius. That is more of an EnemyWithout, though; Morbius seemed sane right up to the end. Morbius may have a mental block preventing him from understanding what has happened, because it was simply too horrible for him to accept that the monster is an inherent part of himself, which meant he had killed all of his friends.
* ''Film/SpiderManTrilogy'':
** In ''Film/SpiderMan1'', this is the origin of the Green Goblin. The process to make him a super soldier also seems to produce a homicidal second personality. Ironically, Norman [[WhatCouldPossiblyGoWrong subjected himself to the serum]] in an effort to prove it would ''not'' have that effect on humans...
** ComicBook/DoctorOctopus in [[Film/SpiderMan2 the second film]] was made crazy by the robot arms. In fact, they slaughtered a room full of medical personnel while Otto was still unconscious. He overcame their programming just in time for a HeroicSacrifice.
** Same with Flint Marko in [[Film/SpiderMan3 the third]]. He wasn't an especially good person before the accident that turned him into Sandman, but afterward he was just nuts. Eddie Brock, on the other hand, started out as a psycho; gaining the Venom symbiote just allowed him to express it in new ways. Flint Marko was ''desperate'', which led to all the bad things he was involved in (including his part in Ben's murder). He needed money desperately to save his daughter's life, and would do anything to get it.
* Franchise/MarvelCinematicUniverse:
** ''Film/TheIncredibleHulk'': The most recent movie finds hardened veteran soldier, Emil Blonsky, given [[PsychoSerum a prototype super-soldier serum]] -- to put "what I know now into the body of a man ten years younger". The combination of being defeated despite this and the taste of such power grow into the classic Comes Great Insanity. Funnily enough, that serum is all but directly stated to be the one that gave ComicBook/CaptainAmerica his powers, but with Blonsky lacking the additional radiotherapy, his insanity is a classic symptom of the SuperSoldier serum gone wrong. Then he demands ([[WhatAnIdiot against repeated warnings]]) a dose of an even ''more'' experimental serum from a much ''less'' reputable source and... let's just say the end results of that little cocktail ain't pretty.
** Similar to ''[[VideoGame/FinalFantasyVI Kefka Palazzo]]'', it is hinted in ''Film/CaptainAmericaTheFirstAvenger'' that [[Comicbook/RedSkull Johann Schmidt]] was the first person to receive the supersoldier serum, but for various reasons, namely a combination of the serum not being perfected yet as well as his dark inner nature, he received a tremendous power boost at the cost of his sanity (and his human form). Steve Rogers himself, however, is selected for being an IdealHero, and thus will be responsible with his power.
* ''Film/UniversalSoldier''. In the sequel, one of them even gets an artificially intelligent, ''Self-Evolving Thought Helix'' military supercomputer downloaded into them.
* ''Film/HollowMan'', starring Creator/KevinBacon.
** Sebastian Caine goes nuts after gaining his ability because he realizes he can get away with a lot of crimes while invisible. It goes from disgustingly creepy (opening a sleeping co-worker's top) to badness and murder real soon. There's some talk about the invisibility PsychoSerum causing insanity, but it's never made clear how much of an effect it's supposed to be having on him.
--->'''Sebastian Caine:''' It's amazing what you can do when you don't have to look at yourself in the mirror.
** As expected, the failure with Caine doesn't stop the government. In the sequel, they use the serum on several more people, including a decorated soldier (Creator/ChristianSlater), who also goes insane and starts killing people. Unfortunately, his soldier training makes him doubly difficult to kill. Unlike the scientist, who already had quite an ego, the soldier goes insane from a side effect of turning cells transparent. Since the skin no longer protects the brain from solar radiation, this causes unavoidable mutations and, as a result, insanity.
* In ''Film/{{Serenity}}'', [[TheWoobie River Tam]] is a paranoid schizophrenic who suffers from hallucinations, delusions, post-traumatic stress, identity and memory disorders, and unfiltered emotional responses. All of this is due to government experimentation on her brain that gave her uncontrolled [[TheEmpath empathic]] PsychicPowers that tie in with [[WaifFu implanted combat abilities]] that make her the single most devastating weapon in the setting.
* In ''Film/ScannersIITheNewOrder'', Peter Drak's rebuttal to David when he tries to reason with him [[YouCouldHaveUsedYourPowersForGood to use his powers for good]] is that killing people is more fun.
-->'''Peter Drak:''' Power doesn't make you good, David. It just makes you powerful.
* Subverted in ''Film/AmazonWomenOnTheMoon,'' when Ed Begley, Jr. plays the son of the original invisible man. He creates a potion that he believes will turn him invisible but not insane. Unfortunately, he becomes insane but visible.
* ''Film/TheMask'': Happens to Stanley Ipkiss whenever he wears the Mask (and when Milo puts it on as well). Dorian Tyrell, not so much. As explained above, the Mask unlocks the suppressed part of a person's psyche. Tyrell, an unrepentant criminal, already had all his nastiness full on the surface, so the Mask just made him invincible and monstrous.
* ''Film/TheCraft'': Nancy. It didn't help that she had a DysfunctionalFamily.
* [[spoiler:Andrew]] from ''Film/{{Chronicle}}''. After a string of events lead him down the DespairEventHorizon, he snaps and goes into full AGodAmI, OmnicidalManiac mode.
* The villain in ''Film/{{Frostbite}}'' stated that his first goal was to ''cure'' vampirism, until he decided that he should ''enhance'' it instead.
* In ''Film/TheWolfMan2010'', [[spoiler:Sir John's lycanthropy has most certainly gone to his head]].
* Averted in ''Film/{{Lucy}}''. The title character stays rational, cool, and focused (perhaps getting even more so) as her power grows to godlike levels.
[[/folder]]

[[folder:Fan Works]]
* ''Fanfic/ChildOfTheStorm'' has Gravemoss, who gets hold of [[TomeOFEldritchLore the Darkhold]] and is completely nuts. However, it is quite clear that [[OmnicidalManiac he was pretty mad to begin with]], so it doesn't make all that much difference to his sanity. [[TookALevelInBadass To his capabilities, however...]]
** The power of the Phoenix is [[TheUnfettered insanely volatile]] by nature, which is why She needs to act through Hosts in the first place - their conscience and rationality acts as a RestrainingBolt. However, her power tends to have a corrosive effect on the sanity of those who aren't totally emotionally balanced and in control; the power of the Phoenix magnifies emotions and is magnified by strong emotion in turn. In other words, you've got a vicious circle where the ''start'' is an insane RealityWarper who can make the Laws of Nature sit down and shut up, one who gets ''even more powerful'' [[SanitySlippage the madder they get,]] and the end is a nigh-omnipotent HumanoidAbomination [[OmnicidalManiac that wants to burn]] ''[[OmnicidalManiac everything]]''. For context, the last time a Host went mad and became the Dark Phoenix [[spoiler: (Surtur)]], ''[[OmnicidalManiac they wiped out a galaxy]]''. Needless to say, there's a good reason why a) the Phoenix is so incredibly picky with Her hosts, b) doesn't usually stick around, c) is universally regarded by gods and demons alike as TheDreaded.
** However, as noted above, the insanity part isn't an inevitable result, with it being pointed out that a sufficiently sane host - not one who suppresses their emotions, someone who accepts them, but isn't controlled by them - is perfectly capable of controlling the power of the Phoenix. But if they slip...
* In the ''Fanfic/OneiroiSeries'' (for ''Webcomic/TheOrderOfTheStick''), this fits [[SplitPersonalityTakeover Deirdre]] to a T. (Though to be fair, she had a few screws loose before she got the Great Power...)
--> '''Deirdre:''' You want me. And you hate it. I suppose it's only natural. I look a lot like [[spoiler:Vaarsuvius,]] don't I?\\
[[spoiler:'''Redcloak [[OedipusComplex (her father)]]:''']] [[spoiler:Tia]], you've gone insane! Please lie down for a second. Take a deep breath. Calm down...\\
'''Deirdre:''' Of course I've gone insane! I'm infused with the magic from a being of pure chaos! But just because I'm insane doesn't mean I'm ''wrong...''
%%* Shinji Ikari in ''Fanfic/PointsOfFamiliarity''.
* ''Fanfic/InnerDemons'': When [[TheDragon Trixie]] invokes the [[ShockAndAwe Storm Avatar]] spell during the Battle of Fillydelphia, it drives her completely around the bend, at least until the protagonists beat her unconscious and break the spell. According to [[MrExposition Lezard]], this happens to [[DangerousForbiddenTechnique anyone who uses the spell]].
* ''Fanfic/FalloutEquestria'': The Goddess, as if the self-given name wasn't a dead giveaway. She is an immensely powerful gestalt psyche that commands the alicorns of the Unity. Unfortunately, being a disharmonious merging of some of the early-war era's most powerful unicorns (including Twilight Sparkle and Trixie, the latter being the first victim and the most dominant persona) means that she's not at all mentally healthy.\\\
In ''[[Fanfic/FalloutEquestriaProjectHorizons Project Horizons]]'', we find that the Goddess likes to take every bad memory, every indication of a shortcoming or flaw, and shunt them into the head of Lacunae, an exiled alicorn whose position at Hoofington means she's not fully connected to the Unity and can be tuned out. Which means that the Goddess won't grow and improve in any way, although Lacunae is becoming a better pony from it.
* ''Fanfic/AnimorphsRedux'': Used for David, the former sixth Animorph, who receives enhanced morphing powers from Crayak that allow him to literally ''absorb'' other beings when acquiring them [[spoiler:(including Cassie)]], but at the cost of all the new memories he's absorbing in the process driving him insane.
* ''Fanfic/TheChangelingOfTheGuard'': [[spoiler:Turns out there's a ''very'' good reason that most [[ShapeShifting Change]][[BeePeople lings]] don't try to shapeshift into [[PhysicalGod Alicorns]]... this trope and total burnout are the results, as Idol learns the hard way]].
* ''Fanfic/RedLightning'': Insanity is almost a requirement to have a superpower.
* Fanfic/TheInfiniteLoops is about a bunch of fictional characters reliving their stories over and over again. They gain incredible powers and also incredible neuroseses. In fact, this trope is referenced by name.
* Princess Twilight Sparkle, the Fourth Alicorn, in ''Fanfic/PinkAlert3''. Ten years of authority have transformed her into a paranoid and aggressive nervous wreck who is little more than a MadGod to Equestria's citizens. She owns a private [[MegaCorp evil corporation]], constantly accuses those around her of being Communists, is so magically unbalanced that she can psychically explode ponies' heads by sneezing too hard, and has a heated argument with an unconscious clone of herself floating in a biogel vat. And all that's just her introductory bonus chapter.
* ''Fanfic/TheEquestrianWindMage'':
** It's explained that the reason Vaati become an outright villain (rather than selfish and neutral) is because the surge of power from when he was first released from the Four Sword went to his head. He's worked hard at getting back to normal.
** When [[VideoGame/StoryOfTheBlanks Grey Hoof]] [[VillainTeamUp allies with]] [[ArcVillain Ganondorf]], the latter grants him a power up in the form of changing him into an alicorn called Nightmare Grave, which [[DrunkOnTheDarkSide renders him even more unstable than he already was]].
* In ''Fanfic/SonicXDarkChaos'', Eric the Hedgehog is a non-evil example of this; [[spoiler: he was created by Maledict along with Sonic and Shadow to create an "Ultimate Weapon"]]. Unfortunately, an [[NoodleIncident unexplained accident]] turned him into a HumanoidAbomination at the cost of damaging his brain, turning him into a CloudCuckoolander ManChild who [[AlmightyIdiot isn't aware of his own powers]].
** Poor, poor [[spoiler: Tsali]]. Being [[spoiler: forcibly turned into a Dark Chaos Energy-powered battle robot]] ''[[AxCrazy really]]'' didn't do good for his sanity.
** [[LovecraftianSuperpower Shroud Tails]], full stop. Although [[BodyHorror considering what happens]], insanity would probably be a step up.
* The ''Fanfic/PonyPOVSeries'':
** Ponies who's hearts call the Spirits of Dark Magic and become [[SuperpoweredEvilSide Nightmares]] gain near god-like power, but there's also no such thing as a ''sane'' Nightmare.
** Dark Magic in general tends to cause it's user to lose it. The reason for this is that it runs on negative emotions that by nature are hard to control. However, should somepony be able to control those emotions, [[DarkIsNotEvil dark magic is no more difficult to control than any other]]. [[spoiler:Sweetie Belle managed this.]]
** Alicorns are an aversion: you only become an Alicorn if you're ''ready'' for the power, as being ready is ''why'' you become one [[spoiler:not being ready means you stop half way and become a Nightmare]].
* Kaguya Otsutsuki in the ''Manga/{{Naruto}}''/''TabletopGame/MagicTheGathering'' story ''[[https://www.fanfiction.net/s/11217239/1/Spark-of-Creation Spark of Creation]]'' is shown to have been driven insane from eating the fruit of the Shinju as she spent the rest of her life with her mind connected to that of a [[EldritchAbomination Blind Eternity]].
* ''[[https://www.fanfiction.net/s/1769554/1/Aftermath-A-Story-of-Blended-Clich%C3%A9s Aftermath: A Story of Blended Cliches]]'' has [[Manga/RanmaOneHalf Ranma]] temporarily slipping into this with a combination of [[Franchise/SailorMoon Pluto's]] meddling and her coming into RealityWarper-level powers. Fortunately for her, [[WhyDidItHaveToBeSnakes a cat]] manages to get her attention. [[spoiler: Unfortunately, [[ForWantOfANail not all versions of here were so fortunate to have caring friends and family]], as another version of her from a parallel dimension was a bit more permanent version of this trope.]]
* ''Fanfic/YetAgainWithALittleExtraHelp'' shows that it doesn't even have to be physical power. Hiruzen Sarutobi, the Third Hokage, straight up admits to Naruto that being Hokage for so long drove him insane -- he just managed to channel it into productive and/or harmless/comical ways, as shown with his near-violent hatred of paperwork.
* ''Fanfic/RainbowDoubleDashsLunaverse:'' During ''Elements of Insanity'', [[spoiler:Lemonhearts]] tries becoming the new God of Chaos. She manages to become a full blown RealityWarper, then gets a visit from Discord warning her that if she wants all that power, she'll have to deal with the insanity that comes with it.
* ''Fanfic/WhiteSheepRWBY'': Jaune at one point mentions that all powerful huntsmen are insane, mostly in small ways but still definitely noticeable. At first his friends have no idea what he's talking about, but as he lists off all the huntsmen he knows, they realize they can't think of a ''single'' counter-example.
[[/folder]]