American Psycho, all in Patrick Bateman's head or some of it real?

I've read this book about a million times and saw the movie- and at first I thought it was real, that he did all of that stuff, and I think in the book he DID do those things because everyone thinks he's a nerd, and make fun of him, and he's sick of the superficial people in his life- all rich, shallow, and have no real life goals. They skate by on their wealth. Note all of the brand names that Patrick mentions. He even tells his fiancee Evelyn that he only works because he wants to "belong" even though his family own the company he works for. I think he snaps, and desperately is crying for help, and when nothing happens, he commits those murders - and in the end of the book, he can't even convince his own LAWYER that he did all of that stuff. So he gets away with it. At the very end of the book it says, "This is not an exit". So I am assuming he's going to continue his torturing and murder. But in the MOVIE, it appeared as if all of it was in his imagination. Hard call. I'd join the Bret Easton Ellis group on MySpace and have a discussion with the members there.

I hope it is just imagination. I am not comfortable with that much violence.