Dissociative Identity Disorder in Primal Fear.
Aaron Stampler (Edward Norton) is an altar boy in the Movie Primal Fear, and has been charged with murder in the first degree. The archbishop was brutally murdered in his chamber at a Chicago church, and Stampler was caught immediately after the crime running away from the church covered in blood. High profile lawyer Martin Vail (Richard Gere) takes the case pro bono, believing that his client is innocent. Vail thinks that Stampler is the victim of a conspiracy and will stop at nothing to prove his innocence. However, a psychiatric evaluation is done, it is seen that Stampler possesses multiple characteristics of Dissociative Identity Disorder. Vail learns that physically Stampler committed the murder, but mentally he was not responsible.
Through the psychiatric evaluations of Stampler an alter personality is brought out. The first time that Stampler's alter personality is seen is in a situation in which he is distressed. The psychiatrist brings up sensitive information about a woman that Stampler believes is his girlfriend, despite the knowledge of her infidelities. Talking about this snaps Stampler into an intimidating persona, quite the opposite of the uneasy, stuttering Stampler. We are only exposed to this hostile persona for a brief moment, and it is made very clear that the psychiatrist is scared of him, as she makes her way toward the door in fear. The next time we see this alter personality is when Vail finds a sexual tape of Stampler and his girlfriend directed by the archbishop. Vail aggressively questions Stampler about the tape and he again snaps into this alter personality. This time however, the personality is very aggressive and we are exposed to many different characteristics of dissociative identity disorder. First we find that the alter personality has a name, Roy. He is extremely rude and seems to make up for the aggressiveness that Stampler lacks.