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The World’s Oldest Nightmare

Sleep Paralysis
The Nightmare by Henry Fuseli

The thing that scared me the most was that I couldn’t move. My body was paralyzed. No, not paralyzed. Something was holding me in place. My eyes were open, and I was aware that I was in my bedroom, but my fiancée and I weren’t alone in the room. There was a figure standing next to my bed trying to hurt me. I screamed for help, but none came for what seemed like minutes.

My shallow breathing and my moans and mumbles continued as my fiancée’s gentle tap on my arm turned into a firmer shake. Eventually, I stirred, sat up, and caught my breath.

In reality, those moans and mumbles were the only sounds I made, and the whole episode lasted mere seconds. It wasn’t a dream, but I wasn’t exactly awake either. I’d just experienced sleep paralysis, a condition that occurs as someone is falling asleep or begins to wake up. It wasn’t the first time I’d experienced it. Like many people, I’d been dealing with it for years. The condition itself goes back a long, long way. In fact, it’s fascinated people for centuries.


Sleep paralysis is responsible for how we talk about bad dreams. That shallow breathing I mentioned is one of the most common features of each episode of sleep paralysis. There are written accounts from ancient cultures of sleepers reporting the feeling that someone was lying on their chest, as if they were being choked. Eventually, people came up with an Olde English word to describe it – maere, which refers to a female evil spirit that lies on top of sleepers and suffocates them. Given that it always came at a certain time of day, they combined it into a new word: Nightmare.

Shallow breathing and the inability to move led to all manner of supernatural accounts of what was happening, and those accounts, in turn, fascinated the writers and artists throughout the centuries. There are references to sleep paralysis in Greek literature and Renaissance art. The Nightmare, a 1781 painting by Henri Fuseli, is regarded as the artist’s depiction of sleep paralysis – complete with a demon sitting upon a woman’s chest. There is speculation that writer J.M. Barrie suffered from the condition, and that his experiences inspired him to write Peter Pan. The fear that comes with the phenomenon has also inspired countless urban legends. One of the most common known as the Night Hag or the Old Hag, but there are versions that originate from every continent.

“It’s interesting that the legend and the experiences exist across cultures and throughout time,” said Charles R. Cantor, MD, DABSM, a professor of Clinical Neurology who sees patients at the Penn Sleep Center.

Cantor says people may hear about these myths from a relative, which could influence what they think is happening during their own episodes. But that doesn’t explain how people from different cultural backgrounds and religious traditions all arrived at the same basic legend.

“The folklore has converged,” Cantor said.


There is, of course, a medical explanation for what’s happening, and the earliest attempt at understanding it may have occurred in Persia in the 10th Century. Akhawayni’s Hidayat al-muta’allemin fi al-tibb was one of the first three manuscripts written in the Persian language. It details anatomy, physiology, and hygiene, as well as methods to treat various diseases. There’s an entire chapter on sleep paralysis.

Since then, of course, modern medicine has provided more clarity.

Sleep paralysis is associated with the period of sleep known as rapid eye movement, or REM sleep.  This is the stage of sleep in which the majority of dreaming occurs. Episodes of paralysis happen most commonly as people are coming out of REM sleep and beginning to wake up, but they can also happen as people are just beginning their REM cycle. Your eyes open and your mind wakes up, but your body remains asleep.

“In most cases, this occurs in people who are sleep deprived or have irregular sleep patterns,” Cantor said. “It can also occur in patients who suffer from narcolepsy, and those patients often experience it going into REM sleep as well as waking up.”


It’s 2010, and I’m lying on a couch in Pittsburgh, Pennsylvania. I’ve been working for several months as an overnight news producer for a local TV station. That means I sleep during the day, assuming I sleep at all. I didn’t know it at the time, but those irregular hours and lack of sufficient rest make me a prime candidate for sleep paralysis. In the hours after dinner but before I go to work, I doze off in front of the TV. I experience the condition for the first time, with my roommate sitting just feet away but unaware of what was happening. That was the start of my long-running battle with sleep paralysis.

Over the years, I’ve hallucinated a variety of scenarios – everything from a demon dragging me around the room to people breaking into my hotel room. Often I’ve found that falling asleep with the TV on allows something on the screen to finds its way into my experience.  

“You can have brief hallucinations as you wake up from REM sleep,” Cantor explained. “When this happens you are in a mixed state of being partly awake and partly asleep. Your hallucination may incorporate something present in the room but misinterpret it.”

In other words, the brain is working against itself. While someone’s eyes are open, their body can’t move, and their brain needs to come up with some kind of explanation for that. Since it’s coming out of the dream space, these hallucinations are not bound by logic, so often the brain reaches for the most supernatural reasoning. Like most sleepers, I still think my calls for help will be answered by someone else in the house. In reality, I may not even be making noise at all.

“There may be a moan or some kind of other vocal indication, but maybe not,” Cantor said.


It’s rare to actually catch an episode of sleep paralysis in the sleep lab, so diagnoses are more commonly based on patient-reported incidents. Cantor says it’s common for people to have a sense of fear or panic when they’ve just experienced an episode, but ultimately the condition won’t cause any physical harm. He says getting into a normal sleep pattern and making sure you get proper rest are ultimately the most effective remedy.

Cantor also says it’s important to make patients aware of the physical process behind sleep paralysis.

“If you understand the mechanism, you’ll be less anxious,” Cantor said. “It’s also important to explain that people think these episodes last longer than they really do.”

Cantor says the shallow breathing is actually normal for REM sleep, as is the lack of movement. We’re just normally asleep during that period, so we don’t notice it.

“Once patients are aware of that, that’s usually enough to take away the fear,” he said. “From there, we can treat a patient’s anxiety if they’re still uncomfortable as they go to sleep each night.”

Cantor also says someone else’s touch can help put an end to the episode and calm the sleeper down. Though my bouts are still disorienting for the first few minutes after I snap out of it, I’m far from the first person to experience the feeling. It turns out I’m just one of the countless people around the world and throughout history to deal with the same exact problem. That’s a comforting thought on its own to keep in mind each time I lay my head down on my pillow.

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