When I was researching material for my next novel, which has a serial killer/psychopath in it, I read other novels with Sk/psychos as major characters so I know what has been done.
Ellis has obviously done his research, and did it shockingly well, on what it is like to live inside the head of a serial killer. He has perfect pitch for characterization, even for this cacophony of a character. Patrick, Ellis's POV character, is a psychopathic serial killer living in 1980s NYC.
The book opens with an absolutely fabulous first page: Patrick riding in a cab with a friend, listening to his shallow friend, and noticing the scenery in NYC, including a quote from Dante's Inferno spray-painted on a wall. It's one of the best first pages I've ever read, and I've read a lot of novels. It perfectly painted the scene and dropped us into the head of the character. I could have forgiven a lot after that first page, but I didn't need to.
Patrick Bateman is a psychopath and a high-functioning paranoid schizophrenic. Less than half of serial killers who are caught are later diagnosed with (or, perhaps, falsely display) schizophrenia. (That was a statistical note. I think the book is better for Patrick's schizo disorder.) Ellis paints a perfect portrait of a psychopath: paint-deep. That's all the deeper that psychopaths are. Inside, they're just an imperturbable deep blue hole of sterile water. There's nothing alive in there. Ellis uses materialism and fashion-consciousness as Patrick's cover for his deep hole of nothingness. The ephemera of brand names and fashion clothes and shoes and jewelry and fashionable restaurants and fashionable foodstuffs (endive!) and quippy comebacks and one-up-man's-ship concerning hipness and coolness were exhausting, which were exactly how they were meant to be.
The sadistic violence, at first, was almost a respite from the banality of Patrick's life, until it, too, became repetitive and boring, which is exactly how Patrick sees it. That's the brilliance of this book. It's a deep, deep portrait of what it's like to feel nothing. Ellis is Jane Austen, delving into the lack of soul.
The note that I found absolutely rang true was when Ellis's POV character, Patrick, has a rare event: an adrenaline rush. Recent research into psychopathic personalities indicates that they have very low arousal levels. Nothing scares them. That's the problem. The fact that Patrick has it when he's trying to get reservations as a trendy restaurant highlights Patrick's inane, shallow character.
One caveat: I can't watch Sex & The City anymore, because all 4 characters now seem as shallow as Patrick Bateman with their shoe and restaurant preoccupations. Or eat endive.
Author of Rabid: A Novel and Callous