Exploding Head Syndrome, is much more common than previously believed, with 18% of college students attacked by loud, non-existent noises. The study also found that one third of those affected, also suffered from isolated sleep paralysis, another frightening disorder.

Exploding Head Syndrome is a parasomnia, or sleep disorder, characterized by experiencing a tremendously loud noise, variously described as gunshots, door slamming, or the clash of cymbals. They are harmless but startling and some thought they had had a stroke. Researchers believe that as the areas of the brain shut down for sleep, a glitch in the auditory neurons causes them to fire at once, creating the noise.

Isolated Sleep Paralysis, another parasomnia, is when the muscles are still paralyzed as if the body is asleep, but the brain begins to wake. In this waking dream, the realization of paralysis creates a nightmare that there is an “intruder”, and has been interpreted as being ridden by witches, seduced by succubi, or abducted by aliens. EHS too has been misconstrued in conspiracy theories of aliens or the government testing psychic weapons.