Ride On The Internal Monologue

I haven't had the opportunity to read the book though I've wanted to after seeing the movie. It seems like a very violent descent into insanity in the movie, cut by pieces of harsh violence and yuppie culture. What I'd be curious of figuring out would be the entire internal monologue. Most of the movie rides on his monologue and very little on what people say or think as if they are just props in his life.

Some of the shots I saw were very aggressive color uses so I would like to see that. Would the violence be show or simply hinted at? I think it'd be fun, not to mention the score seems very interesting!