SLEEP PARALYSIS

Updated January 26, 1999

See our updated article about sleep paralysis on the new Stanford Sleep and Dreams website.

Sleep paralysis consists of a period of inability to perform voluntary movements either at sleep onset (called hypnogogic or predormital form) or upon awakening (called hypnopompic or postdormtal form).

Sleep paralysis may also be referred to as isolated sleep paralysis, familial sleep paralysis, hynogogic or hypnopompic paralysis, predormital or postdormital paralysis

What are the symptoms?

A complaint of inability to move the trunk or limbs at sleep onset or upon awakening

Presence of brief episodes of partial or complete skeletal muscle paralysis

Episodes can be associated with hypnagogic hallucinations or dream-like mentation (act or use of the brain)

Polysomnography (a sleep recording) shows at least one of the following:

suppression of skeletal muscle tone

a sleep onset REM period

dissociated REM sleep

Is it harmful?

Sleep paralysis is most often associated with narcolepsy, a neurological condition in which the person has uncontrollable naps. However, there are many people who experience sleep paralysis without having signs of narcolepsy. Sometimes it runs in families. There is no known explanation why some people experience this paralysis. It is not harmful, although most people report feeling very afraid because they do not know what is happening, and within minutes they gradually or abruptly are able to move again; the episode is often terminated by a sound or a touch on the body.

In some cases, when hypnogogic hallucinations are present, people feel that someone is in the room with them, some experience the feeling that someone or something is sitting on their chest and they feel impending death and suffocation. That has been called the Hag Phenomena and has been happening to people over the centuries. These things cause people much anxiety and terror, but there is no physical harm.

What else can you tell me about sleep paralysis?

Some people with disrupted sleep schedules or circadian rhythm disturbances experience sleep paralysis

A study found that 35% of subjects with isolated sleep paralysis also reported a history of wake panic attacks unrelated to the experience of paralysis

Sixteen percent of these persons with isolated sleep paralysis met the criteria for panic disorder

How can I stop the sleep paralysis?

In severe cases, where episodes take place at least once a week for 6 months, medication may be used.

You may be able to minimize the episodes by following good sleep hygiene:

getting enough sleep

reduce stress

exercise regularly (but not too close to bedtime)

keep a regular sleep schedule

Sleep Paralysis Articles & Web Sites

Diagnostic Classification Steering Committee, Thorpy MJ, Chairman. International Classification of Sleep Disorders: Diagnostic and Coding Manual. Rochester, Minnesota: American Sleep Disorders Association, 1990.

Kryger, Meir H., Roth, Thomas, Dement, William C. Principles and Practice of Sleep Medicine, 2nd Edition. Philadelphia, Pennsylvania: W.B. Saunders Company, 1994.

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