Explainer: what are personality disorders and how are they treated?

Filmmakers know personality disorders make for compelling viewing. Think of attention-seeking Scarlett O'Hara in Gone with the Wind (1939). Or the manipulation and callous disregard for others in Silence of the Lambs (1991), The Talented Mr. Ripley (1999) and Chopper (2000). Then there are the fears of abandonment and emotional instability in Fatal Attraction (1987) and Girl, Interrupted (1999). Cinema is less adept, however, at showing the ordinary joys, heartache and sometimes suicidal despair of the friends, workers or relatives we might know with personality disorders.