What are parasomnias?

Parasomnias are disruptive sleep disorders that can occur during arousals (awakenings) from rapid eye movement (REM) or non-rapid eye movement (NREM or non-REM) sleep. Parasomnias are marked by undesirable physical or verbal behaviors, such as walking or talking during sleep. They occur in association with sleep, specific stages of sleep, or sleep-wake transitions. These can be disruptive to the patient and to the bed partner.

Types of Non-REM Parasomnias

Sleep terrors/night terrors

Night terrors, or sleep terrors, are considered a type of disorder of arousal. The person who is having a sleep terror abruptly arouses from sleep in a terrified state, often crying or screaming, with a rapid heart rate or breathing, sweating, or flushing of the skin. The person may appear to be awake, but is confused and unable to communicate normally.

Night terrors are usually brief but can rarely last up to 30-40 minutes, after which time the person lies down and appears to fall back asleep. People who have sleep terrors frequently do not remember the event the next morning. Night terrors occur during stage 3 sleep (deep sleep) and are more common during the first half of the night.

People who have sleep terrors may pose dangers to themselves or others from jumping on the bed or running around. During the night terror, the person may become more agitated and the episode may last longer if someone tries to interact with or console the person.

Night terrors are fairly common in children aged four to twelve. This sleep disorder, which may run in families, also can occur in up to 3% of adults. Strong emotional tension and/or the use of alcohol can increase the incidence of night terrors among adults.

Sleepwalking (somnambulism)

Sleepwalking is another type of disorder of arousal. It occurs when a person appears to be awake and moving around with eyes wide open, but is actually asleep. Sleepwalkers generally have no memory of their actions. They may wake up in the middle of the episode and appear confused, or get back in bed and go back to sleep without waking.

Sleepwalking most often occurs during deep non-REM sleep (stage 3), early in the night. This sleep disorder is most commonly seen in children aged six to twelve; however, sleepwalking can occur among younger children, adults, and the elderly. Sleepwalking appears to run in families. Sleepwalking can sometimes be dangerous because the sleepwalker is unaware of his or her surroundings and can bump into objects or fall down.

Confusional arousals

Confusional arousals are the final type of disorders of arousal and usually occur when a person is awakened from a deep sleep (stage 3) during the first part of the night. The person remains in bed, sits up, and looks around in a confused manner. The person may cry or be inconsolable. The episodes are generally brief, but can rarely last up to 30-40 minutes. People experiencing confusional arousals react slowly to commands and may have trouble understanding questions they are asked.

Confusional arousals are most commonly seen in young children and go away by age 5. Rarely, they may continue into adulthood or be triggered by stress, illness, other sleep disorders, or sleep deprivation.

Types of REM Parasomnias


Nightmares are vivid dreams during sleep that can cause feelings of fear, terror, and/or anxiety. Usually, the person having a nightmare is abruptly awakened from REM sleep (dreaming sleep) and is able to describe the dream in detail.

Nightmares tend to occur more frequently in the second half of the sleep period. The person having the nightmare often has difficulty going back to sleep.

Nightmares can be caused by many factors, including illness, anxiety, any traumatic event such as the loss of a loved one, or negative reactions to a medication. Contact your doctor if nightmares occur more often than once a week or if nightmares prevent you from getting a good night’s rest for a prolonged period of time.

Sleep paralysis

Sleep paralysis is a sleep disorder in which people are not able to move the body or limbs when falling asleep or waking up because their muscles are briefly paralyzed, even though they are awake. Episodes last from seconds to a few minutes and are distressing, usually causing anxiety or fear.

Sometimes sleep paralysis runs in families, but the cause of sleep paralysis is not known. Sleep deprivation and irregular sleep-wake schedules can also cause sleep paralysis. It is also seen in narcolepsy, a disorder marked by severe excessive daytime sleepiness. An episode of sleep paralysis can often be ended by sound or touch.

REM sleep behavior disorder (RBD)

Rapid eye movement (REM) sleep behavior disorder (RBD) is an REM parasomnia in which people act out dramatic and/or violent dreams during REM sleep. REM sleep usually involves a state of paralysis (atonia), but people with this condition move the body or limbs while dreaming.

Usually, RBD occurs in men aged 50 and older, but it can also happen to women and younger people. It is sometimes caused by certain medications, including most antidepressants. In the diagnosis of RBD, potentially serious neurological disorders must be ruled out. Polysomnography (sleep study) and drug treatments are frequently used to diagnose and treat this disorder.


You should talk to your doctor if you or a family member have any abnormal sleep-related behaviors, especially those associated with injuries or sleep disruption.


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition.This document was last reviewed on: 12/20/2016...#12133