Psychological horror exposes the fears that lurk in the human psyche. These can range from common emotional and psychological weaknesses to the darkest depths of the most depraved minds. Psychological horror can be linked to the supernatural and haunting subgenres, as well, because the protagonist may be confusing the horrors plaguing their mind with something supernatural. Another subgenre closely related to psychological horror is crime and serial killer, as these deal with the depraved acts of a deranged mind.
A staple of psychological horror is the unreliable narrator. Often, the protagonist is in the grips of insanity, and as such, cannot be trusted to tell reality from fantasy. This drags the reader into the madness too, creating suspense and tension. There are exceptions to this, of course, Thomas Harris's The Silence of the Lambs is not narrated by the serial killer Hannibal Lecter, but instead by FBI agent, Clarice Starling. Exceptions to the unreliable narrator in psychological horror tend to mix with the crime and serial killer subgenres.
Themes of psychological horror include reality and perception, which is why an unreliable narrator is vital to this subgenre. The protagonist often faces an internal battle that is more easily relatable than that of other horror subgenres. Using common fears to heighten the protagonist's innate emotion and psychological instability, this subgenre weaves a tightly gripping and emotionally tense journey for the reader.
Level of Characterization: The level of characterization in psychological horror is very high, as the subgenre is, in essence, character driven. It is the protagonist who leads the reader into the depths of insanity. The protagonist must be relatable, though they are struggling with inner demons.
Level of Plot: The level of plot in psychological horror can vary quite a bit, depending on the characters' journey into madness. However, this genre is character driven rather than plot driven. So, expect moderate to low levels of plotting.
Level of Supernatural: The level of supernatural in psychological horror is relatively low, considering that the ghosts and demons in this type of horror are those that plague the characters' psyche.
Level of Scary: The level of scary in psychological horror can vary, generally, however, this is not an in-your-face kind of scare, but instead a creeping horror as the reader slowly realizes the depths of the characters' insanity.
Level of Violence: The level of violence in psychological horror is incredibly variable. There are gorefests such as American Psycho to much more sedate psychological horrors such as The Yellow Wallpaper.
Typical Setting: Unfortunately, there are no typical settings for psychological horror. This subgenre does not require a specific setting to set the mood as so much of the tension derived from the subgenre emerges from the psyche of the protagonist or other characters.
Haunting and supernatural subgenres are related to psychological horror, as some of the best of these subgenre, it is difficult to tell whether the haunting is real or a product of the protagonist's imagination. Also related are the crime and serial killer subgenres as these tend to deal with monstrous acts committed by deviant minds.
Unreliable narrators. If you need to be sure of what is going on while you are reading, this genre may not be for you. Psychological horror treads the line between fantasy and reality in the protagonist's mind, which can sometimes make for a confusing and difficult read. This genre is best for those who are willing to muddle through the journey and don't necessarily need for things to be straightforward.
The Yellow Wallpaper by Charlotte Perkins Gilman- Told in a series of journal entries, this story chronicles a woman's descent into madness when her well-meaning husband attempts to sequester her in a "rest cure" following the birth of their child. The bedroom in the house where they vacation is covered in a hideous yellow wallpaper which quickly becomes the source of the narrator's mania.
The Silence of the Lambs by Thomas Harris- Clarice Starling is asked to interview Hannibal Lecter, an erudite and cannibalistic serial killer, in what she believes is a profile on serial killers. In reality, she has been sent to enlist his help in tracking down another murderer. Lecter trades clues about the killer for details about Starling's own disturbing past.
Psycho by Robert Bloch- Inspired by the life of serial killer, Ed Gein, this novel is the story of Norman Bates, a man whose mother is very protective of him, to the point of murder, even twenty years after her death.
Misery by Stephen King- Writer Paul Sheldon is rescued from a car wreck by his biggest fan who takes him to her home to nurse him back to health. However, when she doesn't like the direction that Sheldon is taking his career, his fan decides to employ some creative control to get him back on track.
We Have Always Lived in the Castle by Shirley Jackson- Merricat, Constance, and their Uncle Julian have always lived a quiet, peaceful existence, far removed from civilization and the townspeople who despise them. All that changes when the girls' estranged cousin, Charles, arrives to woo Constance and uproot their lives. Merricat is convinced that he's a demon and nearly destroys her family in her attempts to be rid of him.
American Psycho by Bret Easton Ellis- In a critique on consumerism, American Psycho introduces Patrick Bateman, a young, wealthy investment banker who seems to have it all. At night, however, Bateman begins experimenting with murder, descending quickly into more violent and depraved escapades, or so he tells us.
Haunted by Chuck Palahniuk- When seventeen writers are invited to a retreat, they are locked in an abandoned theater and told they have three months to write something amazing. Conditions quickly deteriorate as the group feels that only their suffering will make for an excellent work of fiction, kind of like Lord of the Flies, but with writers.
House of Leaves by Mark Z. Danielewski- Johnny Truant makes a macabre discovery in his new apartment. The body of its former tenant along with a manuscript that the old man was working on. As he reads and researches the story, Johnny learns of a house that doesn't seem to exist where supernatural forces drove the family who lived there and researchers into insanity and murder. The more that Johnny investigates the manuscript, the closer he comes to insanity himself.
Diary of a Madman by Nicolai Gogol- All Poprishchin wanted was to be noticed by the beautiful woman whom he had fallen in love with, but as a lowly civil servant, he remains unnoticed. His diary records his descent into madness as his delusions of grandeur grow greater, eventually forcing him into an insane asylum where he believes that he is the king of Spain.
The Drowning Girl by Caitlin R. Kiernan- India Morgan Phelps, otherwise known as Imp, is a schizophrenic who is haunted by a girl she finds near a river. Eva Canning may be part mermaid or part werewolf, or none of these, Imp isn't sure. She can't even trust her own memories, but Imp must discover Eva's secrets before her life and her sanity crumble entirely.