What Is Sleep Paralysis?
Sleep paralysis is a feeling of being conscious but unable to move. It happens when you pass between stages of wakefulness and sleep. During these transitions, you may be unable to move or speak for a few seconds up to a few minutes. You might also feel pressure or a sense of choking, or have hallucinations. Sleep paralysis may come with other sleep disorders such as narcolepsy. Narcolepsy is an overpowering need to sleep caused by a problem with the brain’s ability to regulate sleep.
Is Sleep Paralysis a Symptom of a Serious Problem?
Sleep paralysis is not usually something to worry about. But about 10% of people have recurrent sleep paralysis, which can be a symptom of a more serious problem. If you have frequent episodes of sleep paralysis, then you may have a sleep disorder called narcolepsy. There are also serious mental illnesses that can involve sleep paralysis, including posttraumatic stress disorder (PTSD), bipolar disorder, and anxiety or panic disorders. These conditions can disrupt sleep patterns, making sleep paralysis more likely to happen.
Symptoms of Sleep Paralysis
Not all episodes of sleep paralysis are the same. There are a range of symptoms, which usually begin in your teenage years and may get worse in your 20s and 30s. Symptoms may include:
- Feeling unable to move or speak (atonia)
- A hard time breathing
- Hallucinations, or seeing or hearing things that aren’t there
- Chest pressure
- A sense of suffocation
- Feeling separate from yourself, or out-of-body
- Feeling in danger
Sleep paralysis hallucinations
Sleep paralysis hallucinations are very common, occurring in about 75% of episodes. They are different from dreams. You might sense a dangerous presence or feel like your body is moving. Some hallucinations can cause a feeling of suffocation and chest pressure.
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Sleep Paralysis Causes
Just why or how it happens isn’t clear. Researchers believe sleep paralysis is caused by a disturbed rapid eye movement (REM) cycle because it mostly happens as people are falling into or coming out of REM sleep. During that stage, your brain normally paralyzes your muscles anyway – so they don’t act out your dreams. But during sleep paralysis, your mind is awake, or half awake, and so you are aware you can’t move.
Studies show that about 20% of people have had sleep paralysis at least once. Sleep experts believe sleep paralysis might be partly genetic.
Other causes include stress and disrupted sleep schedules (think jet lag or pulling an all-nighter). Several studies have also found links between social anxiety or panic disorder and sleep paralysis.
When Does Sleep Paralysis Usually Happen?
During an episode of sleep paralysis, you might sense or see things that are not actually there. These hallucinations happen in the early stages of non-REM sleep, unlike dreams or nightmares, which happen later in the sleep cycle. Two types of hallucinations can come with sleep paralysis, either as you’re falling asleep or waking up.
Hypnagogic hallucinations
Also known as waking dreams, hypnagogic hallucinations happen as you’re falling asleep. About 37% of people have them. Often, people see things: entire scenes, faces, shapes, or kaleidoscopic patterns. It’s less common to hear sounds or have physical sensations, such as falling. Whereas dreams often include stories and conversations, hypnagogic hallucinations do not.
Hypnopompic hallucinations
These hallucinations happen as you’re waking up. Like hypnagogic hallucinations, they are most often visual perceptions, but they sometimes involve sounds or physical sensations. An estimated 12% of people have hypnopompic hallucinations.
Sleep Paralysis and Lucid Dreaming
Lucid dreaming and sleep paralysis are not the same. They happen during different stages of sleep and involve different sensations. Both conditions can feel frightening and may interfere with sleep quality.
Sleep paralysis happens as you enter or exit REM sleep, while lucid dreaming occurs during REM sleep. While lucid dreaming, you may feel aware of yourself and be able to control what happens. Unlike sleep paralysis, you won’t feel unable to move during a lucid dream. You might even think you’ve woken up when you actually haven’t.
Some people try to have lucid dreams by using wearable devices, playing video games, or keeping a dream diary. This can be dangerous for people who already have a hard time sleeping or have certain mental health conditions, such as feeling disconnected from reality.