At Tor.com they tagged eight sci-fi & fantasy books that center mental health, including:
The Devil in Silver by Victor LaValleRead about the other entries on the list.
It’s not hard to see how the horror genre can be used to explore mental illness by making the monsters in a person’s head come to life. Set in the fictional New Hyde Mental Institution, the novel begins with the main character, Pepper, being admitted in handcuffs for a 72-hour psych evaluation. On the first night, Pepper is attacked by a terrible creature. When other patients confirm that the creature is real and roams the halls at night, they must come together and face demons from within and without. While the main character has no mental illness, the other patients have ailments that range from schizophrenia to bipolar disorder to obsessive compulsive disorder. The book also tackles the unfortunate reality that is a faulty mental healthcare system that turns its staff and lack of resources into something truly terrifying.
--Marshal Zeringue