Sleep Paralysis Overview

Sleep paralysis sounds unbelievable. You wake from sleep. As you lie in bed, you feel like someone is standing over you in the darkness. You try to move your head only slightly to take a subtle glance, but you can't. Someone – something – is surely holding you down. You attempt to struggle, to thrash your arms and legs, but you are frozen in place. Sheer panic washes over you as your paralysis lingers. Are you going to die? Are you already dead? Though this may sound all too unreal, sleep paralysis is indeed a very real experience. What are the symptoms of sleep paralysis? Learn about the facts, features, frequency, and cure of this condition and how it relates to REM sleep's dreaming characteristics persisting into wakefulness.

First, let's explore some facts about the condition. If you have experienced something similar while awakening, you are familiar with the unforgettable horrors of sleep paralysis. By definition, sleep paralysis is a transient inability to move or speak as one goes from sleep to wakefulness, without other findings characteristic of narcolepsy.

In sleep paralysis, this often occurs while awakening (hypnopompic) as opposed to falling asleep (hypnagogic), which is more common in narcolepsy. It may be more likely to occur towards morning because that is when rapid eye movement (REM) sleep associated with vivid dreaming predominates.

There are some common features that characterize the symptoms of sleep paralysis, including:

• Eye movements are typically preserved.
• It more often occurs while sleeping on one’s back.
• Visual and auditory hallucinations often occur and may include a sense of an evil presence, of being touched, or hearing voices or noises in the room.
• Occasionally faces or people may be seen at the bedside.
• A sense of breathlessness (or chest pressure, even someone standing on one’s chest) may exist. It is still possible to breathe, due to the diaphragm's preserved function.

It is common and may be experienced by 20% to 60% of people, depending on the population examined. In a study of college students, 21% were found to have had at least one episode of sleep paralysis, but only 4% had 5 or more episodes.

It is believed to be precipitated by sleep deprivation, stress, and sleep schedule disruption. In experiments, it has been shown to occur with disruption of rapid eye movement (REM), or dream sleep. It also is associated with anxiety disorders that may themselves lead to lighter sleep, sleep fragmentation, and insomnia. 

Although there may be certain triggers, ultimately sleep paralysis is believed to be a problem with the regulation of REM. During this phase of sleep, the body is kept relaxed so that dreams are not acted out. If this relaxation, or atonia, occurs while the person is awake, it can cause temporary paralysis. The other elements of vivid dream sleep may also intrude into wakefulness. This may be experienced when a REM period is disrupted. 

Obstructive sleep apnea may also trigger awakenings due to breathing disruption and cause sleep paralysis. This might also explain why sleep paralysis is more likely to occur when someone is lying on their back. Associated symptoms such as snoring, witnessed pauses in breathing, gasping or choking, daytime sleepiness, teeth grinding (bruxism), and frequently waking to urinate at night (nocturia) may point to this as the underlying cause of sleep paralysis.

Fortunately, sleep paralysis is harmless. It is self-limited, ending by either falling back asleep or waking more fully out of it. It may occur infrequently. Once it is recognized, reassurance is usually enough. It occurs commonly, and the cause may be relatively benign. There is no risk of dying when these episodes occur. It can still be very scary as it occurs.

Though these episodes may be frightening, the disorder itself is not harmful and will generally resolve on its own. No treatment is needed, but avoiding sleep deprivation, stress, and other precipitants may be helpful. These are summarized in the sleep hygiene guidelines.

For those who suffer from multiple episodes and who are unable to tolerate the psychological distress, a selective serotonin receptor inhibitor (or SSRI) may be prescribed. These medications suppress REM sleep. 

In addition, evaluation by a physician may be important to address sleep, mental health, or other medical disorders that can disrupt sleep. In particular, it may be important to have an evaluation for possible sleep apnea as a contributing cause. If it recurs and is particularly upsetting, an evaluation by a board-certified sleep specialist or a sleep study may be indicated.

Sleep paralysis is a terrifying experience, but the good news is that you may give yourself some reassurance if it should recur. If you wake at night, feeling unable to move, try to relax your mind. Tell yourself that you understand what is happening, that it is not real, and that it will resolve on its own in just a few minutes. Some people even like to fully engage in the experience, pretending that it is like they have become an actor in a scary movie. This might give you a sense of control over an experience that can otherwise make you feel powerless. If you can reassure and distract yourself, falling back asleep, the condition will quickly end. The mind is a strange and powerful thing, and sleep paralysis is another manifestation of its wondrous abilities.