There's one hitting DVD towards the end of this month that might be worth a rent, "Numb" starring Matthew Perry. I've seen it, and thought it was "good, not great", but it had some high points and some really fun characters. It's your basic Romantic-Comedy formula, which will turn off many. However, it touches on mental illness (depersonalization, specificly), and so on a forum that focuses on that sort of thing, it may make a few fans.

http://www.imdb.com/title/tt0795439/