French psychologists recently spent some time analyzing Darth Vader (we're not sure why) and determined that the Sith Lord was mentally ill, according to LiveScience. Specifically, they say he probably has a borderline personality, described by Wikipedia as "a prolonged disturbance of personality function in a person (generally over the age of eighteen years, although it is also found in adolescents), characterized by depth and variability of moods."
The psychologists are going to publish their findings in the journal Psychiatry Research, but LiveScience has a preview:
Skywalker hit six out of the nine borderline personality disorder criteria as defined by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). He only needed to meet five criteria to qualify as suffering from the disorder.
For instance, the future Darth Vader showed both impulsivity and anger management issues as an overexcited, lovelorn Jedi. He went back and forth between idealizing and devaluing Jedi mentors, such as a humorless young Obi-Wan Kenobi.
Abandonment issues also surfaced. Skywalker had a permanent fear of losing his wife, Padme Amidala, and he went so far as to betray his Jedi mentors and companions to try to prevent her death.
Two displays of dissociative episodes took place when Skywalker tried to distance himself from stressful events. The first episode took place after he slaughtered a local tribe of Tuskens responsible for his mother's death. A second episode occurred following his murderous rampage among young Jedi trainees, as he voiced paranoid thoughts about Obi-Wan Kenobi and his wife.
Lastly, any "Star Wars" fan would recognize Skywalker's identity issues and uncertainty about who he was. His fateful turn to the dark side and change of name to Darth Vader could represent the ultimate sign of such identity disturbance, the researchers said.
For some reason the study neglected to mention the other signs of Vader's poor mental health, such as torturing people, destroying entire planets, choking his co-workers to death and cutting off his son's hand. Among other things.