Apparently because psychiatrists have nothing better to do, assembled shrinks at the 160th Annual American Psychiatric Association (APA) meeting handed down their official diagnosis of Darth Vader. He suffered from “borderline personality disorder.”
The docs further intuited that:
Skywalker’s symptoms, including problems with controlling anger and impulsivity, temporary stress-related paranoia, “frantic efforts to avoid real or imagined abandonment (when trying to save his wife at all costs), and a pattern of unstable and intense personal relationships,” including his relationships with his Jedi masters,
indicated that he wasn’t right in the helmet.
Thx to the APA for clearing that up and CBS