You wake in the middle of the night and you feel it: an evil, menacing presence is in the bedroom with you. You open your eyes and your worst nightmare is standing at the foot of your bed. It’s real, and you can’t move a muscle.
It might look like an old hag, an alien, a deceased relative, a shadowy figure or a demon sitting on your chest. No matter what it looks like, this creature leaves you terrified and seemingly trapped in your body, unable to move as it weighs down on you.
“I thought I had a black blanket on top of me,” said Tamara Jones, a 25-year-old college student in Toronto who has experienced the “creature” firsthand. “And then it slid down … and it looked like it flew under the bed. It was a big lump.”
This so-called “sleep demon” has terrorized humans for thousands of years, although science has only managed to explain it within the last century.
The sleep demon is actually a hallucination linked to sleep paralysis, which occurs when a person is jolted awake in the middle of the rapid eye movement (REM) phase of sleep associated with dreaming. You wake up but your brain is still dreaming — and it’s projecting your nightmares into the real world.
Approximately 6-8 per cent of people will experience sleep paralysis during their lives, according to Brian Sharpless, a clinical psychologist and research fellow at Goldsmiths, University of London. Sharpless has worked with hundreds of people suffering from sleep paralysis and has written several books on the subject.
“You’re paralyzed while you’re awake and you’re having hallucinations,” Sharpless told Global News.
“The experiences are so vivid that it makes sense some people might perceive it as real,” Sharpless said.
“It’s like if you start a dream and you wake up in the middle of it,” said Maurice Ohayon, a professor of psychiatry and behavioural sciences at Stanford University. Ohayon has studied sleep paralysis and hallucination for over 20 years, both in Europe and in North America.
There are countless old folktales about spirits and demons that accost sleepers in the middle of the night, often to prey upon or punish the helpless victim. But scientists say this phenomenon is actually a psychological event linked to stress and poor sleep habits — not some paranormal force.
Here’s what you need to know about the “witch” in your bedroom, the “monster” in your doorway and the “demon” on your chest.
What is sleep paralysis?
The brain typically shuts off signals to the rest of the body during the dream phase, Sharpless says.
“It’s probably so we don’t act out our dreams, which could be dangerous,” he said.
However, stress can disrupt the sleep cycle and jerk a sleeper out of his or her dream early, while the body is still in this “lockdown” mode.
This leaves the person fully conscious but unable to move after waking from a dream state, according to the U.S. National Institute of Neurological Disorders and Stroke. Sleep paralysis can have a wide range of additional symptoms, including a heavy feeling on the chest and hypnagogic hallucinations, in which the individual is still dreaming while looking at the real world.
Ohayon says a hypnagogic hallucination is a “distortion of what you see,” not an outright fabrication. In other words, your hallucinations might turn a clothing rack into a towering monster, or a blinking internet modem into a glowing-eyed visitor from another dimension.
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Ohayon says sleep paralysis usually affects people during periods of stress, especially among people in their 20s. It might afflict a person only once in their entire life. However, some people can struggle with it for years.
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Jones says she had her first sleep paralysis episode at age six, and she’s had a few episodes every year since. She remembers being terrified by the paralysis during her first episode.
“I tried to scream for my mom and I remember just not being able to,” she said. “After a while as I got older and it just kept happening, it stopped being scary.”
Jones says her frightening “black blanket” dream was a one-off, and her hallucinations are usually more mundane because she knows what’s happening.
“If I’m going through a more stressful time or there’s been a big change in my life … it can happen every single day for weeks on end,” she said.
Andrew Munday, 36, says he started experiencing sleep paralysis during stressful moments in high school. However, he didn’t start hallucinating until his mid-20s, when he was going through an unstable period at his job.
“There were two weeks in a row when I had one each week, and those ones were much more vivid,” he said. “I sort of woke up — ‘ish’ — from the nightmare and there was still the lingering image from the nightmare floating in front of my face.”
Munday thought he saw a man trying to strangle him in his first hallucination. On the second occasion, he hallucinated a doctor made of burned, sewn-together corpses.
He says the hallucinations faded away after a few seconds, and he hasn’t seen them since.
“I was really concerned about where my life was going, and whether I was going to be able to survive in my job,” he said.
Munday says he ultimately decided to go back to school so he could change careers.
“Once I figured out the way out … that’s when the panic and the paralysis went away.”
Sharpless says sleep paralysis has become more well-known to mainstream audiences thanks to Kendall Jenner, who discussed her own struggles with it in an episode of Keeping Up with the Kardashians a few years ago.
Mastering your nightmares
Ohayon says some people manage to control their sleep paralysis by having lucid dreams in which they can influence the narrative.
“They manage to master their own hypnagogic hallucination,” he said.
Jones says she learned about lucid dreaming from Reddit, and she now uses it to cope with her sleep paralysis.
“I can use lucid dreaming to kind of situate myself,” she said.
“If you’re able to have that awareness and relax your muscles (during sleep paralysis), you’re more likely to just fall back asleep instead of jolting out of it.”
Sharpless says the best way to get through sleep paralysis is to simply wait it out and remind yourself that what you’re seeing isn’t real. Most cases don’t last longer than a minute.
“As soon as movement returns, the hallucinations dissipate immediately,” he said.
The haunted history of sleep paralysis
The sleep demon is perhaps most famously depicted in The Nightmare, a 1781 painting by the artist Henry Fuseli.
The image shows a woman draped across her bed in a restless sleep. A demon known as an incubus crouches on her chest and a horse peeks at her from behind a nearby curtain.
The so-called “sleep demon” has taken many forms over the millennia. Sharpless says these nightmarish visions are usually influenced by the sleeper’s culture, so they will look very different from one era or country to another.
East Asian sleepers often “see” a ghost, he said. Christians in the Middle Ages would see a demon or succubus. Dreamers in Zanzibar claim to have been attacked by a giant black bat called a popobowa.
Many of these demons apply some sort of pressure to the person’s chest — a phenomenon that Ohayon says is linked to the paralysis.
The creature has also seeped into modern pop culture. The titular character in Netflix’s Chilling Adventures of Sabrina faces a witch-like sleep demon in the first season of the show. The 2018 horror film Mara also brings the nightmare of the sleep demon to life.
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A few myths around the sleep demon offer some sort of incentive for the sleeper to move. In some Middle Eastern cultures, for instance, the creature is a jinn wearing a hat. If the sleeper can wake up and snatch the hat, he or she will earn a reward.
“If you’re in France in the 13th century you might see demons or witches, whereas now you’re seeing technologically advanced shadow people,” Sharpless said.
“Every culture puts their own little spin on it, but the core features of sleep paralysis itself — the paralyzing fear, the sense of weight on the chest — these things seem to be invariant.”
He adds that sleep paralysis could explain a spike in reported alien abductions in the 1980s and ‘90s, when paranoia around the phenomenon was at its peak.
Sharpless says it’s also common for people to hallucinate about a recently deceased relative.
“When we’re grieving that often interrupts our sleep, which would make sleep paralysis more likely,” he said.
Ohayon adds that hallucinations are often informed by a person’s own beliefs, and they can sometimes reinforce that person’s belief in the paranormal.
“If the background of the sleeper is very mystical, the content will probably take a more mystical colouration,” he said.
“It’s possible that this is there,” Ohayon said. “But I don’t believe it, personally.”