What is the author's style in It's Kind of a Funny Story by Ned Vizzini?

The book is set in current-day New York and as it is narrated by a teenage boy, uses word and sentence choices that would be typical of someone that age. During scenes featuring some of Craig's high school friends, particularly the book's first chapter, the author uses a fair amount of urban and teenage slang. Sentences such as "Son, what you tryin' to do with my gold, yo?" This, along with other techniques such as having the narrator -- Craig -- say "Ronny is like, blowing smoke . . . " establish a certain mood that gets the reader into the mindset of a group of teenage boys hanging out together, but would be distracting if continued throughout the novel.