Probably The Kite Runner
Books
Book reader community.
Tokyo Doesn't Love Us Anymore was pretty dark at times. Vurt has furry incest so... yeah.
I would have to say American Psycho was pretty fucked up and I don’t think I see it mentioned yet. Way more intense than the movie because it’s a much deeper character study. But man that Patrick Bateman has some fucking crazy thoughts
The Real Story and Lord Foul's Bane by Stephen Donaldson. The man is so utterly casual about rape as plot progression that it leaves me with serious questions about the author.
The Road - Cormac McCarthy. Except I haven't been able to finish it. I know the story, through watching the film, but the imagery in the book is so much more depressing and powerfully disturbing. When I watched the film I felt it for at least a week afterwards. I was getting that feeling each time I'd go to pick up the book of a night. I really want to read it completely, but I just can't work myself up to it.
RIP Cormac McCarthy. I was able to read all of The Road, but only a little bit at a time. It's so bleak, and so realistic.
That’s my answer as well. The book is just so bleak. I read it over a decade ago, and I have thought about re-reading it, but can’t bring myself to do it. It is a really good read though.
The Handmaid’s Tale. I started reading it recently, but it’s too much like current events. I had to stop reading. (Haven’t seen the show, either.)