Dark Angel takes place in the same universe as Strange Days
James Cameron was involved in the production of both of these, and the two share many common themes. A lot of the societal conditions seen in Dark Angel (bad economy, social unrest, police checkpoints, urban decay) are also present in Strange Days, and it's easy to believe that the world of the film could've persisted as it was for another decade before the Pulse caused a total economic collapse and made everything even worse. Also, the presence of sensory-recording SQUID technology in 1999 could be seen as a precursor to all the advanced technology of 2019. Dark Angel is a prequel to Rogue Trooper
The basic premise of a genetically enhanced Super-Soldier on the run from their government is extremely similar, though Rogue was more about Revenge than Max's attempt to simply live like a normal person. It's likely that the Project Manticore evolved into the GI Programme, adding further enhancements, such as resistance to chemicals and diseases, and the biochips, further augmenting their operational capabilities. Ben's problem was genetic after all
But in Alec's case it manifested as manic-depressive disorder, which in Real Life is caused by the same genetic factors as schizophrenia and it's not unheard of in identical twins for one to be schizophrenic and the other manic-depressive. It's not hard to read manic-depressiveness into Alec's behavior, particularly in "The Berrisford Agenda".