Parasomnias & Disruptive Sleep Disorders


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. They can result in undesirable physical or verbal behaviors, such as walking or talking during sleep. Parasomnias occur in association with sleep, specific stages of sleep, or sleep-wake transitions. These parasomnias can be disruptive to both the patient and the bed partner.

What are the types of non-REM parasomnias?

  • Sleep terrors/night terrors: Night terrors or sleep terrors are considered to be a type of disorder of arousal. The person experiencing a sleep terror abruptly arouses from sleep in a terrified state often accompanied by crying or screaming, with 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 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 deep non-REM sleep and are more common during the first half of the night. People experiencing sleep terrors may pose dangers to themselves or others because of 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 4 to 12. 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 and 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, early in the night. This sleep disorder is most commonly seen in children aged 6 to 12. 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 usually occur when a person is awakened from a deep sleep 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 also (rarely) last up to 30-40 minutes. Confusional arousals tend to be prolonged the more others try to interact with them. People experiencing confusional arousals react slowly to commands and may have trouble understanding questions that they are asked. Confusional arousals are most commonly seen in young children and resolve by age 5. Rarely, they may continue into adulthood or be triggered by stress, illness, other sleep disorders, or sleep deprivation.

What are the types of REM parasomnias?

  • Nightmares: 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 detailed dream content. Nightmares tend to occur more frequently in the second half of the sleep period. The person having the nightmare frequently 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. Nightmares occurring more often than once a week or those that create significant sleep disruptions for a prolonged period of time should be evaluated by a medical doctor.
  • Sleep paralysis: Sleep paralysis is a sleep disorder where individuals are not able to move the body or limbs when falling asleep or waking up due to their muscles being briefly paralyzed, even though they are awake. Episodes last 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 characterized by severe excessive daytime sleepiness. An episode of sleep paralysis can often be terminated by sound or touch.
  • REM sleep behavior disorder (RBD): Rapid eye movement (REM) sleep behavior disorder is a REM parasomnia where individuals 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. 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 his disorder.

Living With

When should I call the doctor about sleep problems?

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.

Last reviewed by a Cleveland Clinic medical professional on 04/22/2017.


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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy