Parasomnias include several different disorders that disrupt sleep or reduce sleep quality. These disorders usually affect children but can also occur in adults.

This article discusses the causes, symptoms, and treatment methods for different types of parasomnias.

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The term parasomnia refers to unusual and undesirable behaviors that occur during sleep. Parasomnias can happen during any sleep stage. Sleep stages include non-rapid eye movement sleep (NREM), rapid eye movement sleep (REM), and the transitions between wakefulness and sleeping.

Parasomnias are more common during childhood and become less frequent during adulthood. However, parasomnias affect about 4% of the adult population.

The following factors may increase the risk of parasomnias:

Parasomnias include a wide range of abnormal behaviors, such as walking or talking during sleep. Parasomnias can occur during any sleep stage.

There are two general sleep phases:

  • NREM sleep, consisting of three different stages
  • REM sleep

The body usually cycles through these sleep stages 4–6 times during the night. Each sleep phase involves different types of brain wave activity and physiological changes.

NREM sleep

NREM sleep, also known as quiescent sleep, has three stages:

Stage 1: This includes the transition from wakefulness to sleep. Brain wave activity begins slowing down during this sleep stage.

Stage 2: This is a period of light sleep in which a person’s heart rate and breathing slow down, their body temperature drops, their muscles relax, and their eye movements stop.

Stage 3: This involves deep, restorative sleep. This sleep phase occurs during the first half of the night.

REM sleep

REM sleep begins about one and a half hours after a person falls asleep. The REM sleep phase involves rapid side-to-side eye movements, increased brain wave activity, and irregular breathing.

Examples of parasomnias that occur in the first sleep phase include:


Sleepwalking, also known as somnambulism, is an arousal disorder in which a person gets up and walks around while asleep. Sleepwalking can also involve sleep talking or performing routine activities, such as preparing food or driving.

If a person wakes up in the middle of a sleepwalking episode, they may appear confused or disoriented.

Sleep bruxism

Sleep bruxism is a type of movement disorder that involves clenching or grinding the teeth during sleep. About 13% of adults have sleep bruxism.

Over time, bruxism can lead to headaches, earaches, jaw pain, and abnormal tooth wear.

Confusional arousal

Confusional arousal happens when a person wakes up in a state of confusion. The individual may not know where they are or what they are doing. Other symptoms of confusional arousal include:

  • speaking slower than usual
  • slower reaction time
  • crying
  • shouting
  • poor memory
  • poor coordination

Confusion arousal occurs in about 17% of children. Episodes can last anywhere from a few minutes to several hours.

Sleep terrors

Sleep, or night, terrors are when a person experiences intense feelings of panic or fear during the first third of the night. Sleep terrors occur most often in children between the ages of 3–7 years old.

Sleep terror symptoms include:

  • screaming or thrashing around
  • rapid heartbeat
  • abnormally fast breathing
  • dilated pupils
  • sweating

Episodes last between 10–20 minutes. Most children return to sleep afterward and do not remember having a sleep terror.

REM parasomnias occur during the last sleep stage, which involves heightened brain activity, muscle paralysis, and increased heart rate and breathing.

REM sleep behavior disorder

REM sleep behavior disorder (RBD) occurs when a person physically acts out vivid dreams. Under normal circumstances, the body enters a temporary state of paralysis during REM sleep. However, people with RBD have incomplete or absent paralysis.

RBD does not necessarily occur every night, but an exceptionally realistic, violent, or frightening dream can trigger symptoms. Multiple RBD episodes may occur throughout the night with each REM phase.

A person with RBD may exhibit the following symptoms while sleeping:

  • talking, shouting, or screaming
  • kicking, punching, or thrashing
  • waking up easily
  • clearly remembering dreams

Although RBD does not usually affect a person’s sleep, it can increase a person’s risk of injury.

RBD most commonly affects males over the age of 50. RBDs also have associations with neurodegenerative disorders, such as Parkinson’s disease and Lewy body dementia.


Nightmares are vivid and disturbing dreams that can cause feelings of anxiety, fear, or terror. A person who frequently experiences nightmares or nightmares that significantly affect their sleep may have a nightmare disorder.

Sleep paralysis

The body’s muscles relax as a person falls asleep. During REM sleep, the muscles relax even further and become still. Doctors know this as atonia. Sleep paralysis occurs when muscle atonia happens while a person is still awake.

A person may experience muscle paralysis or the inability to speak while falling asleep or upon waking. A person with sleep paralysis may also experience vivid, waking dreams, or hallucinations, during an episode.

Sleep paralysis episodes last seconds or minutes. Episodes usually resolve spontaneously, but a person can end an episode if they force themselves to move.

  • Bedwetting or sleep enuresis refers to involuntary urination that happens during sleep. Most children wet the bed occasionally. Controlling bladder function during sleep is one of the final stages of toilet training. Doctors do not consider frequent bedwetting to be a parasomnia unless the child is over 5 years old.
  • Exploding head syndrome (EHS) is a condition in which an individual imagines a loud noise, similar to an explosion, just before they drift off to sleep.
  • Sleep-related hallucinations are unreal visual, auditory, or tactile experiences that occur during the transition between sleeping and waking.

Symptoms vary according to the type of parasomnia a person has. General signs to look for include:

  • involuntary behaviors, such as moving, speaking, or walking around during sleep
  • waking up in a state of confusion
  • inability to move or speak when waking up or drifting off to sleep
  • unfamiliar bruises, cuts, or other wounds
  • excessive daytime fatigue

Treatments also vary according to the type, frequency, and severity of a person’s symptoms.

In the first instance, a doctor must identify any underlying health conditions or sleep disorders. Treating an existing condition may also treat the resulting parasomnia.

Talk therapy, cognitive behavioral therapy, and hypnosis may help relieve the symptoms associated with NREM parasomnias.

Tranquilizers, such as benzodiazepines, are useful for treating arousal parasomnias, such as sleepwalking and RBD.

People who live with someone who has a movement-related parasomnia, such as RBD or sleepwalking, may need to sleep in a separate bed. It is also helpful to create a safe environment by removing sharp objects and padding the bedroom furniture.

Most parasomnias typically occur in children — except for RBD, which most commonly affects adult males. Parasomnias may involve a genetic component and tend to run in families.

Most parasomnias do not cause significant adverse health effects. However, some parasomnias, such as RBD, indicate an underlying neurological condition.

The frequency of parasomnia episodes usually decreases as children get older. Medical treatment is not necessary unless a parasomnia significantly disrupts a child’s daily activities or mental health.

Behavioral therapy, relaxation techniques, and hypnosis can help reduce the intensity and frequency of parasomnias that result from stress or anxiety.

A doctor may prescribe tranquilizers or antidepressants for children with severe or frequent sleepwalking or sleep terrors.

Parasomnias can interfere with a person’s quality of sleep. They can also increase the risk of accidents or injuries.

Fortunately, parasomnias are highly treatable and most resolve after childhood.

A person may want to seek medical advice if they notice that they or a loved one exhibit symptoms of a parasomnia.