The term “parasomnia” refers to a wide variety of disruptive sleep-related events. These behaviors and experiences occur usually while sleeping, and are most often infrequent and mild. They may, however, happen often enough or become so bothersome that medical attention is required.


Grinding teeth during sleep is a very common occurrence and little evidence suggests that teethgrinding is associated with any significant medical or psychological problems. In severe cases, mouth devices may help prevent or reduce dental injury.

Disorders of Arousal

The most common parasomnias are “disorders of arousal,” which include confusional arousals, sleepwalking (somnambulism), and sleep terrors. Experts believe the various types of arousal disorders are related and share some characteristics. Essentially, these arousals occur when a person is in a mixed state of being both asleep and awake or coming from the deepest stage of nondreaming sleep. This means that a person is awake enough to act out complex behaviors but still asleep and not aware or able to remember these actions.

Confusional Arousals: Confusional arousals often occur in infants and toddlers but may also be seen in adults. These episodes may begin with the person crying and thrashing around in bed. The individual may appear awake, confused and upset, yet resists attempts by others to comfort or console. It is also difficult to awaken a person who is having an episode of parasomnia. These episodes, which may last up to half an hour, usually end with the person calming, waking briefly, and only wanting to return to sleep.

Sleep Terrors: Sleep terrors are the most extreme and dramatic form of the arousal disorders and are the most distressing to witness. A sleep terror episode often begins with a “bloodcurdling” scream or shout, and may produce signs that suggest extreme terror, such as dilated pupils, rapid breathing, racing heart, sweating, and extreme agitation. During a sleep terror, the victim may bolt out of bed and run around the room or even out of the house. During the frenzied event, victims can hurt themselves or others.

Sleepwalking: Sleepwalking is commonly seen in older children. It ranges from simply getting up out of bed and walking around the room to prolonged and complex actions, including going to another part of the house or even outside to the yard or garage. The sleepwalker may return to bed or awaken in the morning in a different part of the house. Sleepwalkers might carry on conversations that are difficult to understand and make little or no sense. They are capable of acting out complicated behaviors (such as rearranging furniture), but these activities are usually purposeless, and injuries during sleepwalking are uncommon.
In most cases, no treatment is necessary. The sleepwalker and family can be assured that these events rarely indicate any serious underlying medical or psychiatric problem. In children, the number of events tends to decrease with age. These events, however, can occasionally persist into adulthood or may even begin in adulthood.

Nocturnal Seizures

These seizures, which occur only during sleep, can cause the victim to cry, scream, walk, run about, or curse. Like other seizures, these are usually treated with medication.

Rapid Eye Movement (REM) Sleep Behavior Disorder

Muscles that allow us to sit and stand are normally paralyzed during REM sleep. In some people, usually older men, this paralysis is incomplete or absent, allowing the person to “act out” dreams. Such dream- related behavior may be violent and result in injury to the victim or bed partner. Unlike those who experience sleep terrors, the victim will recall vivid dreams. REM sleep behavior disorder can be controlled with medication.

Rhythmic-Movement Disorder

This condition is seen most frequently in young children but may also occur in adults. It takes the form of recurrent head banging, head rolling or body rocking. The individual also may moan or hum. These activities may occur just before falling asleep or during sleep. Medical or psychological problems are rarely associated with rhythmic-movement disorder. Behavior treatment may be effective in severe cases.

Sleep-Related Eating

A rare type of sleepwalking is “sleep-related eating.” People with this disorder experience recurrent episodes of eating during sleep, without being aware of what they are doing. Sleep-related eating might occur often enough to result in significant weight gain. Although it can affect all ages and both sexes, it is more common in young women.

Sleep Starts

Most people have experienced the common “motor” sleep start — a sudden, often violent, jerk of the entire body that occurs upon falling asleep. Other forms of sleep starts also occur just as sleep begins. A “visual” sleep start is a sensation of blinding light coming from inside the eyes or head. An “auditory” sleep start is a loud snapping noise that seems to come from inside the head. Such occurrences can be frightening, but are harmless.


Sleep talking is a normal phenomenon and is of no medical or psychological importance.