I'll list Shock Corridor under non-horror but it terrified me when I first saw it on television in cathode ray tube black and white. So, yes, I was too young for it. But it still scares me. A journalist fakes insanity to go after a story. The story starts to go after him instead. Here's the pressbook to serve as a warning to you. But definitely see it. It just may scare and unsettle you as much as it did me.
Comic book reader version: Download Shock Corridor Pressbook