10 Terrifying Horror Movies Set In Asylums

10. The Ninth Configuration (1980)

Written, produced, and directed by The Exorcist author William Peter Blatty in his directorial debut, cult classic The Ninth Configuration is easily the strangest entry on this list.

Also released under the title Twinkle, Twinkle, "Killer" Kane, this flick takes viewers to an abandoned castle that's been repurposed into a psychiatric hospital by the US government. The goal is to discern which of the Vietnam veterans in the institution are faking symptoms of psychosis. Distinguished psychiatrist Colonel Kane (Stacy Keach) is brought in to assist.

Upon arrival he pays particular attention to one Billy Cutshaw (Scott Wilson), a former astronaut who had a severe breakdown before a mission to the moon. But as events progress Kane’s own sanity is thrown into question as madness gradually takes hold.

The Ninth Configuration begins life as an oddball comedy as viewers are introduced to the inmates and equally peculiar staff. With a distinct lack of conventional scares and genre tropes, you’d be forgiven for assuming this acclaimed classic doesn't qualify as a horror.

It’s only later when Blatty begins to explore themes of religion, identity, and existence that the horror elements begin to seep into the film.

The result is an unrelenting cinematic experience viewers won’t soon forget.