i need books where people are miserable

i really want to read something hopeless, where a person suffers because of their own sick mind, i don't even know how to phrase it tbh

the first thing that came to my mind was "no longer human" which i tried to read a couple of years ago, but it didn't click for some reason. and Kafka. i'd also like to read good books about body dysmorphia(body horror maybe?)

also this is kind of a different category but my favorite movies and shows are perfect blue, the truman show, and black mirror. so basically i want to find something similar, anything that fits even loosely. sorry for such a messy text, i really don’t know how to explain it i don’t even understand what exactly i want to read💀