Igby Goes Down (2002)

Insanity is relative.

Igby Slocumb, a rebellious and sarcastic 17-year-old boy, is at war with the stifling world of old money privilege he was born into. With a schizophrenic father, a self-absorbed, distant mother, and a shark-like young Republican big brother, Igby figures there must be a better life out there -- and sets about finding it.