Horror that operates through the mind, questioning perception, sanity, and reality rather than relying on external threats.
Psychological horror scares you from the inside out. Instead of monsters or supernatural threats, the danger lives in the character's mind: unreliable perception, paranoia, guilt, obsession, or the slow dissolution of sanity. The reader is never sure what's real. The genre exploits our trust in our own minds and asks: what if you can't trust yours?
Psychological horror is the most literary branch of the horror genre and the one with the most crossover appeal. It teaches you to write unreliable perspective, build tension through ambiguity, and trust your reader to be unsettled by uncertainty. These are skills that elevate any kind of fiction.
A house that's bigger on the inside, nested narrators, and typography that literally makes the page feel wrong.
A narrator whose version of events gradually reveals itself to be far more disturbing than she admits.
Is the girl possessed or mentally ill? The novel refuses to answer, and the ambiguity is the horror.
Write a scene from the perspective of a character who believes something is true that the reader gradually realizes is false. Don't signal the unreliability overtly. Let small details accumulate until the reader's trust in the narrator quietly collapses.