As soon as I opened my eyes in the middle of one February night, I knew something was wrong. This hunch was confirmed when I tried to lift up my head, only to be met with disobedience from my neck muscles and nerves. I tried to shift my leg, raise an arm, lift a finger, but everything stayed pinned in place. I tried to say something to my roommate, sleeping peacefully just a door away, but no dice. I was stuck.
As one might imagine, this made me pretty anxious. That anxiety transitioned into full-blown panic just seconds later, though, when out of the corner of my eye, I saw a figure standing next to my desk, mere feet away. Seemingly faceless, it moved toward the bed until it was standing directly over me. Then, in an even more unfortunate turn of events, it seemed to get on my chest. My brain was doing its best to make me yell or flail, but my body remained out of commission. I’d seen enough mediocre horror movies to know that this was the end of the line for me.
But miraculously, I snapped out of it. I sat up in bed, panting, and it slowly became clear to me that I was safe again.
It wasn’t a normal bad dream, though. I may not have been completely awake, but I was very aware, stuck in a living nightmare. The experience was, as I would soon discover, a bout of sleep paralysis.
Although freaky, sleep paralysis is far from a freak event. A 2011 article published in the Sleep Medicine Reviews aggregated the results of numerous reputable studies and found that 7.6 percent of the general population has experienced sleep paralysis in their lifetime. That number balloons to 28.3 percent for students, and 31.9 percent for psychiatric patients.
The causes behind it aren’t clear, but it’s likely that lack of sleep is a main factor, and having a preexisting mental condition also seems to heighten a person’s chances. Sleep paralysis has also been discussed as a potential indicator for narcolepsy. But as for the biological processes that go on, experts generally agree that it occurs due to a disruption of the sleep cycle at its deepest point.
“What happens is, people wake up in the middle of REM sleep,” said Dr. Khalid Ismail, director of the Center for Sleep Medicine at Tufts Medical Center. “Some parts of the brain are awake, others are still in REM. You’re partially awake.”
The brain shuts down all body movement during REM sleep. This is a good thing most of the time, because many of us would be dead, injured, or possibly imprisoned if we acted out our dreams while asleep. But when we’re awakened in this state, the self-preservation mode comes back to bite us. All of a sudden, our brain is conscious but our body isn’t.
Being paralyzed temporarily is bad enough, but our brain decides to up the ante by playing tricks on us. Because we’re still partially asleep, a nightmare can seem transposed onto reality. The hellish vision I had, for instance, is a very common side effect of sleep paralysis. Ismail experienced something similar during his own episode, which happened during his chronically sleep- deprived medical school days.
“Somebody was in the room and I wasn’t able to react,” he recalled. “Some intruder was walking around my room, and I couldn’t do anything about it.”
In this day and age, given the research done on the topic, it’s easy enough to realize afterward that what happens during sleep paralysis isn’t real. All you have to do is hop on your iPhone for a second to verify that you aren’t losing it.
But consider not having that knowledge readily available. Episodes would feel less like harmless nightmares and more like paranormal visits, since everything feels so realistic. This, in part, could explain the origin of many spooky tales.
“Sleep paralysis is at least a piece of the puzzle in understanding many scary nocturnal events. It’s often been associated with ghosts, aliens, and demonic visitations,” said Brian Sharpless, coauthor of 2015’s “Sleep Paralysis: Historical, Psychological, and Medical Perspectives.”
Sharpless breaks down sleep paralysis hallucinations into three subtypes: intruder in the room, like the experience Ismail had; incubus, the experience I had, which is generally described as something on top of you, pressing down; and vestibular-motor, where you feel illusory body sensations, like floating, for instance.
The experience was, as I would soon discover, a bout of sleep paralysis.
“If you think about these three experiences,” said Sharpless, “they map onto a good number of paranormal events. In ‘alien abductions,’ for instance, you might feel illusory movements like levitating.’”
Sharpless, for his part, had his first sleep paralysis experience just a year and half ago. He was a little more prepared than the rest of us, given that he’s been studying the phenomenon since 2010.
“I had it when returning from an international talk. I was really jetlagged . . . I just looked at the figure and realized I was finally having sleep paralysis,” he said.
One of the facets of sleep paralysis that fascinates Sharpless the most is the global and historical reach of it. “I haven’t identified a culture that hasn’t reported sleep paralysis,” he said. “[And] each culture puts their own spin on the experience.”
In fact, according to Sharpless, the true original meaning of “nightmare” comes from sleep paralysis experiences. Before the 20th century shift toward the more modern usage of the word, a nightmare specifically meant a nighttime event in which “[t]he core features … included waking up paralyzed, feeling pressure on your body, and seeing or feeling a being on top of you,” he said. This is perfectly and horrifically illustrated by the 1781 painting by John Henry Fuseli, “The Nightmare.”
Different cultures and languages have used a variety of different descriptions throughout history — Sharpless and a colleague compiled more than 100 recorded references to sleep paralysis. In Turkey, for instance, it is called “the dark presser.” In Germany, it’s been referred to as “the witch presser” or “the elf presser.” In Sri Lanka, it’s simply “the ghost that forces you down.”
I think scary as hell is an accurate enough description.Alex Frandsen can be reached at firstname.lastname@example.org.