History Main / MurderMakesYouCrazy

%%* Tommy from ''Franchise/FridayThe13th.''

* More than one writer has cited this trope as a reason behind Franchise/{{Batman}}'s TechnicalPacifist stance. He fears he is so close to the ragged edge of sanity already that if he starts killing ''anyone'', [[NotSoDifferent he will not be able to stop]]. In one alternate universe shown in ''Comicbook/CountdownToFinalCrisis'', he kills TheJoker and then decides he might as well kill ''every other supervillain'' -- and succeeds.

[[/folder]]

[[folder: Real Life ]]
* There may be some TruthInTelevision, in the cases of crimes of passion. More research would be needed, though.
* There is an actual condition called Post Traumatic Stress Disorder, which happens mainly to ex-soldiers, and is pretty much the RealLife basis for the ShellShockedVeteran. Killing people isn't the only way it can come about, though.

Normally, in RealLife (although there may be exceptions), a person is ''already'' crazy and/or violent before they contemplate murder. In television however, circumstances will cause you to commit murder, and then you keep killing. No, this trope is '''not''' about [[NeverOneMurder murder where you have to keep killing in order to ''hide the evidence'']]. Instead, it's about murder ''actually warping the mind'', either by [[MyGodWhatHaveIDone guilt]] or as the [[NeverMyFault process of rationalizing the murder]] sets in.

Usually this involves some lead-up event where they are sane but [[GainingTheWillToKill have decided to kill]] from being put into a situation where unless they are an ActualPacifist they will practically be forced to murder because of a no-win situation. After doing the actual murder however, the act makes them evil, or in [[MurderMakesYouCrazy this trope]], insane.

The difference between this and a normal FaceHeelTurn, is that it usually follows [[BreakTheCutie excessive amounts of guilt and gloom]], and results not in evil, but rather madness. Still, it can probably be viewed as a sister trope. Likewise for SlowlySlippingIntoEvil, since it isn't evil you slip into, but rather madness.

* Light Yagami of ''Manga/DeathNote''. He's an ordinary school student until he writes the first name. After that, he develops delusions of grandeur and wants to cleanse the world of evil (leaving himself as the only evil person, as Ryuuk points out). In the manga, the reader first sees how Light has already killed numerous targets before flashing back to his first kill for maximum shock value and to show how far he has already fallen in such a short time.
* Yuno Gasai of ''Manga/FutureDiary'' is probably the TropeCodifier. Not only is she pretty much the poster girl for {{Yandere}}, but her entire issues be pinpointed exactly to the point where she lost it, [[spoiler: snapped on her parents for their abusive and controlling behavior, and killed them]]. In fact, in a version of the past where she didn't do this, she recovered and became a hopeful and optimistic girl.
* ''Manga/ACruelGodReigns'' Jeremy suffers multiple [[spoiler: nervous break-downs, hallucinations, and becomes a drug addicted prostitute]] as an after effect of killing his step-father and his mother (although his mother was an accident.)

* [[spoiler: Reiner Braun]] from ''Manga/AttackOnTitan'' is driven insane by the guilt of having committed mass murder, developing a DoubleConsciousness in order to keep going. In particular, the murder of [[spoiler: Marco Bott]] to protect their secret causes him to completely break down, immediately lapsing into a Dissociative state and pleading to know ''why'' their friend is being eaten.

* In the Post-Crisis universe, ''{{Superman}}'' is forced to kill three Kryptonian criminals that wiped out an alternate version of Earth. Since there are no longer any officials to sentence them, Superman appoints himself JudgeJuryAndExecutioner and uses kryptonite (keeping himself in a KryptoniteProofSuit of course) to kill them. Superman was later so emotionally disturbed about this that he developed a SplitPersonality that took the form of an extreme NinetiesAntiHero.
* More than one writer has cited this trope as a reason behind Franchise/{{Batman}}'s TechnicalPacifist stance. He fears he is so close to the ragged edge of sanity already that if he starts killing ''anyone'' [[NotSoDifferent he will not be able to stop]]. In one alternate universe shown in ''Comicbook/CountdownToFinalCrisis'', he kills TheJoker and then decides he might as well kill ''every other supervillain'' -- and succeeds.

* ''Film/SweeneyToddTheDemonBarberOfFleetStreet'' both plays this trope straight and subverts it; although the trigger for Sweeney's crowning moment of crazy is the Judge escaping before "Epiphany", Sweeney has already been forced to kill Pirelli, an AssholeVictim who tried to blackmail him, but was thoroughly unrelated to his initial reason for revenge. His descent from [[TheDeterminator a single-minded]] [[RoaringRampageOfRevenge vigilante out for revenge]] to a [[AxCrazy raging psychopath]] [[TheUnfettered willing to kill anybody]] arguably comes about as a result of the earlier kill, in that he's already begun killing men who aren't responsible for ruining his life.
* ''Film/EvilDead2'' - Ash, [[WhatHappenedToMommy after being attacked by his possessed girlfriend Linda]].

* Used in ''Literature/TheDresdenFiles'' and the reason for the First Rule - magic is an expression of will given form so using it to kill someone is particularly warping and even addictive. Non-magical killing doesn't cause this, though Harry confesses in one book that he's haunted by having to execute two people, and fears that this makes him a monster as well.
* Both ''Theatre/{{Macbeth}}'' and his wife has this happen to them after their murder of Duncan.
* Creator/AgathaChristie's Literature/HerculePoirot discusses this trope a few times. He notes that once someone gets over the initial mental hurdle of taking someone's life for the first time, to them murder becomes an acceptable solution to any number of life problems.
* In the Literature/HarryPotter series, committing murder ''tears the soul''. The soul can heal from this, provided both pieces are left next to each other.

* ''TabletopGame/WorldOfDarkness'': Due to the way [[KarmaMeter Morality system]] is designed, this trope is almost unavoidable. When you murder someone, your psyche cracks a bit and make it easier the next time you have/want to do it again. Do this often enough, and you turn into Hollywood-style psycho, known as [[TabletopGame/HunterTheVigil Slashers]].

* In ''VideoGame/{{Fahrenheit}}'', Lucas ''thinks'' that he is going crazy after (unwillingly) murdering a man but it is later revealed that [[spoiler:his mind has been manipulated and damaged by one of the villains all along]].
* ''VideoGame/OracleOfTao'' has Ambrosia who is more or less a little crazy already (being a MoodSwinger SugarAndIcePersonality with a LiteralSplitPersonality), but in a Bad Ending she goes noticeably over the edge after killing [[IncorruptiblePurePureness an angel]]. She starts talking about "balancing the scales" (which, since she [[spoiler: created the universe from a DreamApocalypse]], means basically destroying everything), and goes on a homicidal rampage, even killing her own party.

* Happens to [[spoiler: Clover]] in ''VisualNovel/NineHoursNinePersonsNineDoors'' during "axe ending". [[spoiler: She starts by wanting to kill Santa and Seven believing them to be responsible for death of her brother. June was trying to defended them so she killed her too. After 3 murders she snapped completely and killed Junpei for no particular reason.]]

* There may be some TruthInTelevision, in the cases of crimes of passion. More research would be needed though.
* There is an actual condition called Post Traumatic Stress Disorder, which happens mainly to ex-soldiers, and is pretty much the RealLife basis for the ShellShockedVeteran. Killing people isn't the only way it can come about though.

* Yuno Gasai of ''Manga/FutureDiary'' is probably the TropeCodifier. Not only is she pretty much the poster girl for {{Yandere}}, but her entire issues be pinpointed exactly to the point where she [[spoiler: killed her parents]]. In fact, in a version of the past where she didn't do this, she recovered and became a hopeful and optimistic girl.

* This is part of the sanity-tracking game mechanics of LoneSurvivor. Killing mutants might be the most expedient way of getting past them, but it has a negative effect on your score, and the more you kill, the worse it gets.

* Every time you kill someone in ''VideoGame/YandereSimulator'', you lose Sanity. Lose too much Sanity without an effort to regain it, and people won't want to deal with you -- least of all Senpai.

* More than one writer has cited this trope as a reason behind Franchise/{{Batman}}'s TechnicalPacifist stance. He fears he is so close to the ragged edge of sanity already that if he starts killing ''anyone'' [[NotSoDifferent he will not be able to stop]].

* In ''{{Fahrenheit}}'', Lucas ''thinks'' that he is going crazy after (unwillingly) murdering a man but it is later revealed that [[spoiler:his mind has been manipulated and damaged by one of the villains all along]].

* Used in ''Literature/TheDresdenFiles'' and the reason for the First Rule - magic is an expression of will given form so using it to kill someone is particularly warping. Non-magical killing doesn't cause this, though.

* More than one writer has cited this trope as a reason behind {{Batman}}'s TechnicalPacifist stance. He fears he is so close to the ragged edge of sanity already that if he starts killing ''anyone'' [[NotSoDifferent he will not be able to stop]].

* Yuno Gasai of ''FutureDiary'' is probably the TropeCodifier. Not only is she pretty much the poster girl for {{Yandere}}, but her entire issues be pinpointed exactly to the point where she [[spoiler: killed her parents]]. In fact, in a version of the past where she didn't do this, she recovered and became a hopeful and optimistic girl.

* Light Yagami of ''Manga/DeathNote'', in the anime only. He's an ordinary school student until he writes the first name. After that, he develops delusions of grandeur and wants to cleanse the world of evil (leaving himself as the only evil person, as Ryuuk points out). In the manga, the reader first sees how Light has already killed numerous targets before flashing back to his first kill for maximum shock value and to show how far he has already fallen in such a short time.

-> ''"Killing... after a while it infects you, and once it does you're never rid of it."''
->-- '''[[Series/DoctorWho The Doctor]]''' in "The Doctor's Daughter."

* SweeneyToddTheDemonBarberOfFleetStreet both plays this trope straight and subverts it; although the trigger for Sweeney's crowning moment of crazy is the Judge escaping before "Epiphany", Sweeney has already been forced to kill Pirelli, an AssholeVictim who tried to blackmail him, but was thoroughly unrelated to his initial reason for revenge. His descent from [[TheDeterminator a single-minded]] [[RoaringRampageOfRevenge vigilante out for revenge]] to a [[AxCrazy raging psychopath]] [[TheUnfettered willing to kill anybody]] arguably comes about as a result of the earlier kill, in that he's already begun killing men who aren't responsible for ruining his life.
* ''Franchise/EvilDead 2'' - Ash, [[WhatHappenedToMommy after being attacked by his possessed girlfriend Linda]].

* Tommy from ''Franchise/FridayThe13th.''

--> ''"Killing... after a while it infects you, and once it does you're never rid of it."''
-->-- '''[[Series/DoctorWho The Doctor]]''' in "The Doctor's Daughter."

--> ''"Killing... after awhile it infects you, and once it does you're never rid of it."''
-->-- [[DoctorWho The Doctor]] in "The Doctor's Daughter."

* In ''Series/DoctorWho'', The Doctor tries to advise his daughter [[spoiler: grown in a military cloning device as a soldier]] that violence is not the answer. There have been more than a few times where people go WhatTheHellHero to The Doctor, so he's definitely speaking from experience, when he believes war can mess one up.

* Used in DresdenFiles and the reason for the First Rule - magic is an expression of will given form so using it to kill someone is particularly warping. Non-magical killing doesn't cause this, though.

* AgathaChristie's HerculePoirot discusses this trope a few times. He notes that once someone gets over the initial mental hurdle of taking someone's life for the first time, to them murder becomes an acceptable solution to any number of life problems.
* In the Literature/HarryPotter series, committing murder ''tears the soul''. The soul can heal from this, provided both pieces are left next to eachother.

* Light Yagami of ''Manga/DeathNote'', in the anime only. He's an ordinary school student until he writes the first name. After that, he develops delusions of grandeur and wants to cleanse the world of evil (leaving himself as the only evil person, as Ryuuk points out). In the manga, this first target is skipped over, showing instead Ryuuk showing up after he's already killed numerous targets.

* ''ACruelGodReigns'' Jeremy suffers multiple [[spoiler: nervous break-downs, hallucinations, and becomes a drug addicted prostitute]] as an after effect of killing his step-father and his mother (although his mother was an accident.)

Usually this involves some lead-up event where they are sane but have decided to kill from being put into a situation where unless they are an ActualPacifist they will practically be forced to murder because of a no-win situation. After doing the actual murder however, the act makes them evil, or in [[MurderMakesYouCrazy this trope]], insane.

* ''Anime/PuellaMagiMadokaMagica'': In the manga ([[DependingOnTheWriter but not the anime]]), [[spoiler:Sayaka]]'s final straw is her murder of two random guys who, all things considered, did't really deserve being killed in cold blood. [[AndThenJohnWasAZombie By her own admission, she is such a fool]].

* SweeneyToddTheDemonBarberOfFleetStreet both plays this trope straight and subverts it; although the trigger for Sweeney's crowning moment of crazy is the Judge escaping before "Epiphany", Sweeney has already been forced to kill Pirelli, a (comparatively) innocent man. His descent from [[TheDeterminator a single-minded]] [[RoaringRampageOfRevenge vigilante out for revenge]] to a [[AxCrazy raging psychopath]] [[TheUnfettered willing to kill anybody]] arguably comes about as a result of the earlier kill, in that he's already begun killing men who aren't responsible for ruining his life.

* There is an actual condition called Post Traumatic Stress Disorder, which happens mainly to ex-soldiers, and is pretty much the RealLife basis for the ShellShockedVeteran.

* In the HarryPotter series, committing murder ''tears the soul''. The soul can heal from this, provided both pieces are left next to eachother.