It's hard to come up with a more intense, interesting, and thought-provoking movie about mental health than Girl, Interrupted
(1999). We discuss hospitalization, various mental illnesses, coping mechanisms, and how it's sometimes hard to tell when your loved one has a mental disorder.
Borderline Personality Disorder: https://www.nami.org/Learn-More/Mental-Health-Conditions/Borderline-Personality-Disorder
Girl, Interrupted IMDb: http://www.imdb.com/title/tt0172493/