What are parasomnias?

Parasomnias are disruptive sleep disorders that can occur during arousals from rapid eye movement (REM) sleep or arousals from non-rapid eye movement (NREM) sleep. Parasomnias:

Types of Parasomnias


Nightmares are vivid nocturnal events that can cause feelings of fear, terror, and/or anxiety. Usually, the person having a nightmare is abruptly awakened from REM sleep and is able to describe detailed dream content. Usually, the person having a nightmare has difficulty returning 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 nights rest for a prolonged period of time.

Sleep terrors/night terrors

A person experiencing a night terror or sleep terror abruptly awakes from sleep in a terrified state often accompanied by crying or screaming, an increase in heart rate or breathing, sweating or flushing of the skin. The person may appear to be awake, but is confused and unable to communicate. Night terrors last about 15 minutes, after which time the person usually lies down and appears to fall back asleep. People who have sleep terrors usually don't remember the events the next morning. Night terrors occur during stage 3 sleep (deep sleep). People experiencing sleep terrors may pose dangers to themselves or others because of jumping on the bed or running around. 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 occurs when a person appears to be awake and moving around with eyes wide open but is actually asleep. Sleepwalkers have no memory of their actions. Sleepwalking most often occurs during deep non-REM sleep (stage 3), early in the night. These episodes vary widely in complexity and duration. This 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 can fall down.

Confusional arousals

Confusional arousals usually occur when a person is awakened from a deep sleep during the first part of the night. This disorder, which also is known as excessive sleep inertia or sleep drunkenness, involves an exaggerated slowness upon awakening. People experiencing confusional arousals react slowly to commands and may have trouble understanding questions that they are asked. The childhood form is benign and resolves spontaneously while the adult variant may persist for a long time with consequences such as sleep related injury, sub-optimal performance at work, etc.

Sleep paralysis

People with sleep paralysis are not able to move the body or limbs when falling asleep or waking up. Brief episodes of partial or complete skeletal muscle paralysis can occur during sleep paralysis. 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 characterized by severe excessive daytime sleepiness. This disorder is not harmful, but people experiencing sleep paralysis often are very fearful because they do not know what is happening. An episode of sleep paralysis often is terminated by sound or touch. Within minutes, the person with sleep paralysis is able to move again.

REM sleep behavior disorder (RBD)

People with rapid eye movement (REM) sleep behavior disorder 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 the disorder also can occur in women and in younger people. In the diagnosis and treatment of RBD, potentially serious neurological disorders must be ruled out. Polysomnography (sleep study) and drug treatments are involved in the diagnosis and treatment of this disorder.

Sleep enuresis

In this condition, also called bedwetting, the affected person is unable to maintain urinary control when asleep. There are two kinds of enuresis—primary and secondary. In primary enuresis, a person has been unable to have urinary control from infancy onward. In secondary enuresis, a person has a relapse after previously having been able to have urinary control. Enuresis can be caused by medical conditions (including diabetes, urinary tract infection) or by psychiatric disorders. Some treatments for bedwetting include behavior modification, alarm devices, and medications.


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



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. For additional health information, please contact the Center for Consumer Health Information at the Cleveland Clinic (216) 444-3771 or toll-free (800) 223-2273 extension 43771. If you prefer, you may visit or This document was last reviewed on: 4/22/2017