It's a Young Adult novel that I first read in 2002 or 2003. The story revolves around a boy living in a dystopian setting in which a sort of virtual reality simulation is extremely popular. I believe it involved some sort of needle that would allow the user to experience a virtual reality while in reality they were in a sort of temporary coma body-wise. The main boy has some sort of condition (I don't remember if it's a disease or an allergy) to this stuff, so he can't do the virtual reality simulations. I don't remember a lot of the plot, but I do remember that where the boy lives is ruled by this cruel kid with a terrible reputation. Near the end of the novel the main character finds this terrible boy emaciated and hooked up to the virtual reality stuff, and he realizes that all the stories about him are fake, because he has clearly been hooked up to the simulations for a very long time.
I think you might mean The Last Book In The Universe. The protagonist lives in a gang-ridden world after civilization is destroyed in an earthquake. Many people choose to use virtual reality simulations to escape the situation, but the protagonist is epileptic and cannot. Much of the book's plot involves him rediscovering literacy.