We’ve all got that one weird friend of a friend of a friend. You know, that one mystical person who sold coffee to a celebrity or got murdered by a vengeful spirit at a sleepover or got abducted by aliens. So when your oversharing coworkers says their cousin went to summer camp with a guy who’s uncle got abducted by aliens, you always wonder if alcohol was involved.
But what if the only thing involved in that alien abduction was sleep?
The normal process of falling asleep involves a few important components. The most obvious is a loss of consciousness, but after the sleeper becomes unconscious, the body paralyzes itself in order to keep from acting out its dreams. When someone regains recovers from their paralysis without regaining consciousness, they go sleepwalking. When the opposite happens, chaos ensues.
Waking up from sleep without recovering from the body’s natural state of paralysis is called “sleep paralysis”, which makes sense. But sleep paralysis is not nearly as innocuous as it sounds. Apparently the body’s natural reaction to waking up completely unable to move is to hallucinate wildly until your brain gets its stuff together.
One of the most common hallucinations, experienced by nearly everyone who has ever had sleep paralysis, is the sensation of a threatening presence in the room, known as “the intruder” or “the incubus”. Since eye movement is the only movement possible during sleep paralysis, sleepers often claim to watch the intruder enter the room or approach them. One of my roommates once hallucinated a friend of ours sitting in a chair in the corner of her room before standing up, turning into a demon, and attacking her. She unfortunately experiences recurrent isolated sleep paralysis (RISP), a rare condition that causes her to experience extended episodes of sleep paralysis chronically, even as often as twice in one night. Most people who experience sleep paralysis, however, are experiencing isolated sleep paralysis (ISP) and will likely only have an episode once in their life. I had an episode several years ago in which I hallucinating a man made of steam kneeling above my head and slowly attempting to suffocate me. After about thirty seconds (standard duration for a sleep paralysis episode) I was able to lift my arm to touch what I thought was the steam man’s face, only to wake up with my arm sticking straight up into empty air.
The exact cause of sleep paralysis and the reason for its hallucinatory effects are somewhat unclear. For people with ISP, it is more or less a quick glitch in the brain’s sleep pattern. But for people with RISP, the explanation is more complicated. It’s definitely a neurological cause, likely related to other sleep disorders such as narcolepsy and sleep apnea, as well as anxiety disorders, depression, and migraines. It’s believed the the hallucinations are the brain’s attempt to explain the paralysis, which in my opinion makes the brain sound like kind of an idiot. The brain, unable to recognize that it’s just done the waking-up process in the wrong order and nothing is actually horribly wrong, recognizes the vulnerable state of the paralyzed body and goes into high alert. Unable to recognize that the brain itself is the cause of this vulnerable and intensely anxious state, the brain tries to determine the threat by just creating one in the form of a non-exist demon. Essentially your brain gets confused, panics, and then gets real goofy about trying to resolve the issue.
Many people who believe to be possessed by demons, visited by ghosts, abducted by aliens, or to have had out-of-body experiences may just be experiencing sleep paralysis. These incredibly vivid hallucinations are extremely easy to mistake for reality, and they often involve strange-looking creatures entering the room uninvited and threatening harm to the vulnerable sleeper. I myself was nearly convinced I had been almost murdered by a ghost until I remembered that ghosts aren’t real and starting doing some research on my experience.
Sleep paralysis is a shockingly common subject of artwork and folklore, although many artists in earlier eras did not know that sleep paralysis was what they were depicting. The incubus and succubus, folkloric demons believed to force sexual encounters with incapacitated sleeping victims, exist in various forms in a wide variety of cultures and are believed to be an early interpretation of sleep paralysis hallucinations. Cousin to the incubus and succubus is the night hag (also known as an ifrit, mare, dab tsog, pisadeira, or phi am in various cultures), who sits on the chests of innocent sleepers just for kicks. Most believe indigestion or sleeping with a full stomach attracts the night hag, and the only way to get rid of it is to touch it, steal something from it, or fight its crushing weight enough to move one’s body. Henry Fuseli’s 1781 painting The Nightmare depicts a demon sitting on a woman’s chest as she sleeps, as does Eugène Thivier’s 1894 sculpture by the same name. Even Ebenezer Scrooge in Charles Dickens’ A Christmas Carol may be experiencing sleep paralysis when he is visited in his bed by the unwelcome ghost of his former business partner.
The best advice for avoiding sleep paralysis is to know it can’t really be avoided, although the Household Cyclopedia (1881) suggests you not study immediately after eating and that you avoid foods that give you gas, so that’s always an option.