Sleep terror disorder
Sleep terror disorder is defined as repeated temporary arousal from sleep, during which the affected person appears and acts extremely frightened.
Sleep terror disorder is sometimes referred to as pavor nocturnus when it occurs in children, and incubus when it occurs in adults. Sleep terrors are also sometimes called night terrors, though sleep terror is the preferred term, as episodes can occur during daytime naps as well as at night. Sleep terror is a disorder that primarily affects children, although a small number of adults are affected as well.
Causes and symptoms
The causes of sleep terror are for the most part unknown. Some researchers suggest that sleep terrors are caused by a delay in the maturation of the child's central nervous system. Such factors as sleep deprivation, psychological stress , and fever may also trigger episodes of sleep terror.
The symptoms of sleep terror are very similar to the physical symptoms of extreme fear. These include rapid heartbeat, sweating, and rapid breathing (hyperventilation). The heart rate can increase up to two to four times the person's regular rate. Sleep terrors cause people to be jolted into motion, often sitting up suddenly in bed. People sometimes scream or cry. The person's facial expression may be fearful.
People experiencing sleep terror disorder sometimes get out of bed and act as if they are fighting or fleeing something. During this time injuries can occur. Cases have been reported of people falling out of windows or falling down stairs during episodes of sleep terror.
People experiencing sleep terror are not fully awake. They are nearly impossible to bring to consciousness or comfort, and sometimes respond violently to attempts to console or restrain them. In many cases, once the episode is over the person returns to sleep without ever waking fully. People often do not have any recollection of the episode after later awaking normally, although they may recall a sense of fear.
Episodes of sleep terror usually occur during the first third of a person's night sleep, although they can occur even during naps taken in the daytime. The average sleep terror episode lasts less than 15 minutes. Usually only one episode occurs per night, but in some cases terror episodes occur in clusters. It is unusual for a person to have many episodes in a single night, although upwards of 40 have been reported. Most persons with the disorder have only one occurrence per week, or just a few per month.
Sleep terror disorder is much more common in children than it is in adults. It is estimated that approximately 1%–6% of children in the United States experience sleep terror at some point in their childhood. For most children, sleep terrors begin between the ages of four and 12. The problem usually disappears during adolescence. Sleep terror disorder appears to be more common in boys than in girls; some studies have reported that preadolescent boys are the group most commonly affected. No figures are available for the rates of the disorder in different racial or ethnic groups. Sleep terrors in children are not associated with any psychological disorders.
Fewer than 1% of adults have sleep terror disorder. For most adults, sleep terrors begin in their 20s or 30s, although it is possible for someone to suffer from episodes of sleep terror from childhood onward. In the adult population, sleep terrors affect both sexes equally. They are, however, often associated with psychological disorders, most commonly anxiety, personality, or post-traumatic disorders. People who have a family history of sleep terrors or sleepwalking disorder are about 10 times more likely to develop sleep terror disorder than those who do not.
Sleep terror is diagnosed most often in children when parents express concern to the child's pediatrician. A fact sheet from the American Academy of Child and Adolescent Psychiatry suggests that parents consult a child psychiatrist if the child has several episodes of sleep terror each night, if the episodes occur every night for weeks at a time, or if they interfere with the child's daytime activities. The diagnosis is usually made on the basis of the child's and parents' description of the symptoms. There are no laboratory tests for sleep terror disorder. In adults, the disorder is usually self-reported to the patient's family doctor. Again, the diagnosis is usually based on the patient's description of the symptoms.
Sleep terror is characterized by an abrupt arousal from sleep followed by symptoms of extreme fear. The symptoms often include screams, rapid heartbeat, heavy breathing, and sweating, as well as a subjective feeling of terror. According to the Diagnostic and Statistical Manual of Mental Disorders , fourth edition, text revision ( DSM-IV-TR ), which is the standard reference work used by mental health professionals to diagnose mental disorders, people with sleep terror disorder do not respond to attempts to comfort or awaken them. In order to meet criteria for the diagnosis, the patients must not be able to recall their dreams, and they must not remember the episode itself. In addition, the episodes may not be attributed to a medical condition or drug use.
Sleep terror disorder is frequently confused with nightmare disorder . The two are similar in the sense that both are related to bad dreams. Nightmare disorder, however, involves a significantly smaller amount of physical movement than does sleep terror. Normally, people experiencing nightmare disorder do not get out of bed.
Moreover, people experiencing nightmare disorder often have problems going back to sleep because of the nature of their dream. Most people experiencing sleep terrors, however, go back to deep sleep without ever having fully awakened. People experiencing nightmares can generally remember their dreams and some of the events in the dream leading up to their awakening. People often awake from nightmares just as they are about to experience the most frightening part of a disturbing dream. People experiencing sleep terrors, however, can sometimes recall a sense of profound fear, but often do not remember the episode at all.
If sleep terror episodes are infrequent, then treatment may not be necessary as long as the episodes are not interfering significantly with the person's life. Some people may want to rearrange their bedroom furniture to minimize the possibility of hurting themselves or others if they get out of bed during a sleep terror episode. To keep children from becoming overly worried about their sleep terrors, experts suggest that parents avoid placing unnecessary emphasis on the episodes. Psychotherapy is often helpful for adults concerned about the specific triggers of sleep terror episodes.
Several different medications have been used to treat sleep terror disorder, with varying degrees of success. One of the most common is diazepam (Valium). Diazepam is a hypnotic (sleep-inducing medication), and is thought to be useful in the prevention of sleep terror episodes because it acts as a nervous system depressant. There are many different types of hypnotics, and choosing one for a patient depends on other drugs that the patient may be taking, any medical or psychological conditions, and other health factors. Most studies of medications as treatments for sleep terror disorder have been done on adult patients; there is little information available on the use of medications to treat the disorder in children.
In most children, sleep terror disorder resolves before or during adolescence without any treatment. Adults often respond well to diazepam or another hypnotic. Psychotherapy and avoidance of stressors that may precipitate terror episodes may be helpful as well. Episodes of sleep terrors often decrease with age. This decrease is due to the fact that the amount of slow-wave sleep, which is the sleep phase during which terror episodes usually occur, declines with age.
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American Academy of Child and Adolescent Psychiatry. 3615 Wisconsin Avenue NW, Washington, DC 20016-3007. (202) 966-7300. Fax: (202) 966-2891. <www.aacap.org> .
American Academy of Sleep Medicine. 6301 Bandel Road NW, Suite 101, Rochester, MN 55901. (507) 287-6006. <www.asda.org> .
American Academy of Child & Adolescent Psychiatry (AACAP). "Children's Sleep Problems." AACAP Facts For Families Pamphlet #34. Washington, DC: American Academy of Child & Adolescent Psychiatry, 2000.
Tish Davidson, A.M.