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Parasomnias: 6 Truly Creepy Things that Can Happen While You Sleep

Have you ever woken up in the middle of eating a sandwich? Felt paralyzed in your bed? Or maybe you heard an earth-shattering explosion just as you were falling asleep that nobody else heard. We'll learn more about parasomnias, the strange medical phenomena that fascinate people and stump doctors.

By
Jade Wu, PhD
8-minute read
Episode #327
The Quick And Dirty

Parasomnias refer to a group of sleep disorders that involve frightening or strange experiences. Sleeping enough, keeping a consistent sleep-wake schedule, minimizing alcohol and drugs, and managing stress are helpful for parasomnias. If these symptoms persist even without these factors, talk to your doctor about getting a sleep study.

In 1833 in Springfield, Massachusetts, a young servant woman named Jane began to attract attention from the foremost medical experts of the time. She was a sleepwalker. And her sleepwalking was extraordinary—she would get out of bed and complete full sets of chores like setting the table and arranging clothes. One witness even saw her thread a needle, sew a cloth bag, and use the bag to cook a piece of meat in a boiling pot of water ... all in the dark, while she was asleep.

Sadly, Jane’s strange symptoms landed her in an insane asylum. The eminent doctors tried all sorts of tinctures, medicines, and even leeching, but her sleepwalking was never cured. She eventually convinced her doctors to give up on her and she was able to go back to living a quiet life.

But Jane wasn’t the first or the last sleepwalker to capture the public's morbid curiosity. In 1987, a Canadian man named Kenneth Parks drove 14 miles to his in-laws’ home and killed his mother-in-law with a tire iron. Covered in blood, he went straight to the nearest police station to confess. He claimed that he was asleep during this whole event, and a later sleep study showed that his brain activity was indeed very abnormal. Ultimately, the jury found him to be innocent of murder. Since then, a few dozen homicide cases have hinged on the “sleepwalking” defense.

What are parasomnias?

"Parasomnias" is a term that covers a range of sleep disorders and disturbances from common occurrences to the truly bizarre.

The extreme sleepwalking events I described are very rare—you're incredibly unlikely to thread a needle or commit homicide in your sleep. In fact, sleepwalking homicides are extremely rare, and there’s still doubt as to whether sleepwalking is really what happened in those cases.

But sleepwalking to some degree is surprisingly common, and so are other parasomnias. Let's take a look at some different parasomnias and talk about what you can do about them.

Sleepwalking (somnambulism)

Sleepwalking’s medical name is “somnambulism.” If you’ve ever woken up and found yourself outside your bed, with no idea how you got there, you may have experienced it. You may even have woken up to find yourself looking at a half-eaten cake, in the middle of the phone conversation, or even driving. That’s why sleepwalking isn’t just spooky for onlookers, it can actually be dangerous!

More than half of adult sleepwalkers have exhibited violent behaviors while sleepwalking, and 17% have even ended up with enough injury to need medical attention

In fact, more than half of adult sleepwalkers have exhibited violent behaviors while sleepwalking. Seventeen percent have even ended up with enough injury to need medical attention, like one patient in the study who jumped out of a third-floor window while totally asleep. The real enigma is that most sleepwalkers don't feel pain while sleepwalking, even if they're getting injured.

What to do about sleepwalking

If you see someone sleepwalking, gently guide them back to bed. Don’t try to wake them up. If you sleepwalk repeatedly, talk to your doctor about reviewing your medications, or possibly getting a sleep study. Meanwhile, you may want to lock the front door, hide your keys, and put away anything else that can be dangerous before going to bed.

And weirdly enough, sleepwalking can be triggered by strong positive emotions. Of course, you shouldn’t avoid all things joyful for fear of sleepwalking. But consider meditation and a wind-down period before bedtime to help you to be even-keeled as you enter sleep.

Sleep-related eating disorder 

One disorder closely related to sleepwalking is sleep-eating, where someone involuntarily eats food while sleepwalking.

Those who have a sleep-related eating disorder cannot control their food intake during the night, leading to significant weight gain.

Like sleepwalkers, sleep-eaters often also have insomnia and sleepiness during the day. But it's possible that some of them have more awareness during sleep-eating episodes than regular sleepwalkers. Sometimes, this can lead to significant weight gain because those who have a sleep-related eating disorder cannot control their food intake during the night.

What to do about sleep-related eating disorder

Avoiding alcohol and drugs, decreasing stress, and keeping a regular sleep-wake schedule can help. If not, a sleep doctor may prescribe medications or check to see if there are other underlying health problems.

REM-behavior sleep disorder (RBD)

REM-behavior sleep disorder (RBD) can look like sleepwalking, but it actually happens when someone acts out their dreams.

One difference between RBD and sleepwalking is that RBD happens during REM sleep, which you have in the second half of the night, whereas sleepwalking usually happens during deep sleep, which you get in the first half of the night.

During an RBD episode, the sleeper is dreaming and acting out whatever is happening in their dream, and it’s usually a violent action like fighting or running.

Another difference is that during a sleepwalking episode, the sleeper is not dreaming and is not at all aware of what they’re doing. For the most part, their behaviors are calm and neutral. But during an RBD episode, the sleeper is dreaming and acting out whatever is happening in their dream, and it’s usually a violent action like fighting or running, though sometimes it can also be a  sophisticated action like playing the piano.

Usually, your brain essentially "turns off" your muscles (something called "REM atonia") so you don’t act out your dreams. For someone with RBD, this safety mechanism fails and the dream spills over into the body, playing it like a puppet.

What to do about REM-behavioral sleep disorder

Safety is the most important concern with RBD. Many patients had no idea they were acting out their dreams until their bed partner ended up with a black eye or they woke up to find themselves terrorizing the dog. So listen to your spouse when they say that you’ve been acting out at night. Then, consult a sleep neurologist, who can help you to manage your symptoms.

Sleep terrors (a.k.a. night terrors) and nightmares

Sleep terrors seem, well, terrifying. You might sit up in bed or even jump out of bed, screaming and inconsolable for a few seconds or even minutes.

Sometimes, people use the terms "sleep terrors" and "nightmares" interchangeably. But they’re totally different. Nightmares are dreams that are disturbing, sometimes scary enough to wake us up in a panic, and might even affect our mood during the day. These typically happen in the second half of the night because dreaming happens mostly during REM sleep. I've dedicated a whole previous episode to nightmare prevention

Someone in the middle of a sleep terror episode is not really awake—they’re disoriented, terrified, and can’t coherently talk about what’s happening.

Sleep terrors, in contrast, happen during deep sleep in the first half of the night, and there are no dreams involved. Someone in the middle of a sleep terror episode is not really awake—they’re disoriented, terrified, and can’t coherently talk about what’s happening. The next morning, they may not even remember what happened. If someone woke you during a sleep terror, you would have no idea why you felt so scared.

What to do about sleep terrors

Sleep terrors are not uncommon in young children. Thankfully, sleep terrors are not harmful in and of themselves, and they're more scary for parents than for the kids themselves, who don’t even remember their nighttime horrors next day.

Parents should not try to wake the child up during a sleep terror, but instead, calmly monitor their safety during the event and act normally during the day. If the sleep terror tends to happen at the same time of the night, you can gently wake up your child half an hour before the usual terror time. This can often prevent the sleep terror from happening.

Making sure your child gets enough sleep may help too. Don’t worry—having sleep terrors doesn’t mean that your kid has emotional problems, and they’ll most likely outgrow the disorder ... so you can finally get some sleep, yourself!

Sleep paralysis and hypnogogic/hypnopompic hallucinations

If you’ve ever woken up completely unable to move, and perhaps felt a heaviness on your chest and a sense of fear or doom … you have experienced a sleep paralysis episode.

People describe seeing shadowy figures in the room or standing over their bed, or spiders crawling their walls or in their bed.

Sometimes, along with the paralysis, people also see, hear, or feel things that aren’t there. These are called "hypnogogic" or "hypnopompic hallucinations." Usually, people describe seeing shadowy figures in the room or standing over their bed, or spiders crawling their walls or in their bed. We talked about the sleep paralysis and related hallucinations in a recent episode, including how these experiences have spawned alien abduction theories.  

What to do about sleep paralysis and hypnogogic/hypnopompic hallucinations

Just like for most other parasomnias, consistently getting enough sleep, keeping a steady sleep schedule, and avoiding substances could help.

Exploding head syndrome

And for a truly bizarre parasomnia, there is the aptly named exploding head syndrome. This is where a person hears or feels a very loud noise in their head, usually during that blurry period just before falling asleep or just upon waking. The loud noises can feel like an explosion inside their head, though there’s usually no pain involved. Or they can also sound like loud banging or crashing, a door slamming, thunder, or electric crackles.

The loud noises can feel like an explosion inside their head, though there’s usually no pain involved.

What to do about exploding head syndrome

Sleep scientists have not reached a consensus on exactly why this rare symptom happens, but it seems that stress and emotional tension might make it more likely to occur. Usually, just putting a name to it and learning that this scary experience doesn’t indicate some serious medical issue is enough to help.

Parasomnia tips roundup

Most of the parasomnias we covered here may be decreased by having better quality sleep overall, or they might be a medication side effect or a symptom of a more serious medical condition. Here are a few things you can do to get a handle on your sleepwalking, sleep paralysis, or any of the other strange symptoms of the night.

  • Ensure safety. Lock doors and put away car keys, sleep in a separate room from your spouse, and keep sharp objects out of reach.
     
  • Stabilize your sleep schedule. Parasomnias often happen because of an incomplete transition between wake and sleep. By keeping a steady biological clock, you can help your brain to transition between sleep and wake normally.
     
  • Get enough sleep. Sleep deprivation is a common trigger for parasomnias like sleep paralysis. This might be why students, who are notorious for pulling all-nighters, are more prone to this symptom.
     
  • Minimize alcohol and drugs. Substances that affect your brain function can affect your sleep and dreaming, too.
     
  • Ask your doctor about your medications. Sometimes, medications prescribed for insomnia, depression, or other psychological disorders might induce parasomnias as a side effect. There may be options to adjust your medications if they’re causing nighttime problems.
     
  • Ask your doctor about getting a sleep study. Sometimes, symptoms like sleep-related hallucinations and sleep paralysis might indicate narcolepsy. Acting out dreams and having frequent nightmares might indicate a neurological or psychiatric condition, which also requires specialized care. But sometimes, parasomnias like sleep terrors or exploding head syndrome might not indicate anything at all. Getting a full work-up with a sleep specialist can help to either reassure you or point you toward the right treatment.
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All content here is for informational purposes only. This content does not replace the professional judgment of your own mental health provider. Please consult a licensed mental health professional for all individual questions and issues.

About the Author

Jade Wu, PhD Savvy Psychologist

Dr. Jade Wu was the host of the Savvy Psychologist podcast between 2019 and 2021. She is a licensed clinical psychologist. She received her Ph.D. from Boston University and completed a clinical residency and fellowship at Duke University School of Medicine.