10 Best Slow-Burning Psychological Horror Movies

10. Martha Marcy May Marlene

We'll start this list off with a movie that walks the line between psychological horror and psychological thriller, but ultimately lands firmly in the center of the former rather than the latter.

In Martha Marcy May Marlene, after escaping from a crazed cult a young woman, Martha, tries to go back to having a normal life while staying with her family. However, her paranoia begins to get the better of her as she suspects that she might not be out of the woods just yet.

Martha Marcy May Marlene is terrifying at every moment. Each and every frame feels like a threat, like anything could happen at anytime. You'll find yourself just as paranoid as Martha, constantly scanning the screen for any sign of the cult.

There's one moment in particular where she has a flashback to the time she helped them in a home invasion that will no doubt put you on edge and have you double checking your home security system.

Martha Marcy May Marlene feels violating, using its slow pacing as nothing more than a tool to drag out this feeling of vulnerability to its furthest extent.