Me, Myself and I (1992)

A romantic comedy with multiple personalities.

Diane is a growling, howling urban nightmare, suffering from paranoia, nymphomania, and a really bad hair day. Her neighbor, a TV writer, is subject to Diane's constant commentary on sex, violence and invisible persecutors through paper-thin walls. When Diane manages to seduce him, the two jaded New Yorkers discover that love works in mysterious ways.