Sleepwalking disorder, also called somnambulism, is characterized by repeating episodes of motor activity during sleep such as sitting up in bed, rising, and walking around, among others. The person appears to be awake because their eyes are usually open and they can maneuver around objects, but is considered asleep.
Sleepwalking disorder is one of several sleep disorders listed in the Diagnostic and Statistical Manual of Mental Disorders , often called DSM-IV-TR , produced by the American Psychiatric Association and used by most mental health professionals in North America and Europe to diagnose mental disorders.
Sleepwalking episodes usually occur during the first third of the night during the deepest phase of sleep. The episodes can last anywhere from a few minutes up to one hour, with five to 15 minutes being average. Sleepwalkers appear to be awake but are typically unresponsive to individuals who attempt to communicate with them. Persons who sleepwalk typically have no memory or awareness of their actions or movement upon waking.
Causes and symptoms
There appears to be a genetic component for individuals who sleepwalk. The condition is 10 times more likely to occur in close relatives of known sleepwalkers than in the general public. These families also tend to be deep sleepers.
Sleepwalking may also be triggered by fever, which directly affects the nervous system, general illness, alcohol use, sleep deprivation, and emotional stress . Hormonal changes that occur during adolescence, menstruation, and pregnancy can be also be triggers for sleepwalking. Sleepwalking episodes are more likely during times of physiological or psychological stress.
Certain classes of medication have also been shown to precipitate sleepwalking episodes in some individuals. These include: Anti-anxiety or sleep-inducing drugs, antiseizure medications, stimulants, antihistamines, and anti-arrhythmic heart drugs.
The DSM-IV-TR specifies six diagnostic criteria for sleepwalking disorder:
- Repeated episodes of rising from bed during sleep: These episodes may include sitting up in bed, looking around, and walking, and usually occur during the first third of the night.
- Is unresponsive to attempts at communication: During sleepwalking, the person typically has eyes open, dilated pupils, a blank stare, and does not respond to another's attempts at communication. Affected persons typically are only awakened with great difficulty.
- No recollection of the sleepwalking incident: Upon waking, the person typically has no memory of the sleepwalking events. If the individual does awaken from the sleepwalking episode, they may have a vague memory of the incident. Often, sleepwalkers will return to bed, or fall asleep in another place with no recall as to how they got there.
- No impairment of mental activity upon waking: If an individual awakens during a sleepwalking episode, there may be a short period of confusion or disorientation, but there is no impairment of mental activity or behavior.
- Causes significant distress to life situations: Sleepwalking causes significant disruption of social and occupational situations, or affects other abilities to function.
- Not due to substance use or abuse: Sleepwalking disorder is not diagnosed if the cause is related to drug abuse, medication, or a general medical condition.
Sleepwalking can occur at any age but is most common in children, with the first episodes usually between the ages of four and eight years. The peak of sleepwalking behavior occurs at about 12 years of age. Between 10 and 30% of children have had at least one episode of sleepwalking. Sleepwalking disorder is seen in only 1–5% of children and occurs more frequently in boys. Adults who sleepwalk typically have a history of sleepwalking that stems back to childhood. Sleepwalking events occur in approximately 1–7% of adults while sleepwalking disorder occurs in about 0.5%.
The line that separates periodic sleepwalking from sleepwalking disorder is not clearly defined. Individuals or families most often seek professional help when the episodes of sleepwalking are violent, pose a risk for injury, or impair the person's ability to function. For a diagnosis of sleepwalking disorder to be made, the person must experience a significant amount of social, occupational, or other impairment related to the sleepwalking problem. Episodes that have a long history extending from childhood through adolescence and especially into adulthood are more likely to be diagnosed with sleepwalking disorder.
Since the individual cannot recall the sleepwalking activity, diagnosis by means of interview is of little benefit, unless it involves someone who has witnessed the sleepwalking behavior. The preferred method for accurate diagnosis is through polysomnography . This technique involves hooking electrodes to different locations on the affected person's body to monitor brain wave activity, heart rate, breathing, and other vital signs while the individual sleeps. Monitoring brain-wave patterns and physiologic responses during sleep can usually give sleep specialists an accurate diagnosis of the condition and determine the effective means of treatment, if any.
Sleepwalking disorder can be difficult to distinguish from sleep terror disorder . In both cases, the individual has motor movement, is difficult to awaken, and does not remember the incident. The primary difference is that sleep terror disorder typically has an initial scream and signs of intense fear and panic associated with the other behaviors.
Treatment for sleepwalking is often unnecessary, especially if episodes are infrequent and pose no hazard to the sleepwalker or others. If sleepwalking is recurrent, or daytime fatigue is suspected to result from disturbed sleep patterns, polysomnography may be recommended to determine whether some form of treatment may be helpful. If stress appears to trigger sleepwalking events in adults, stress management, biofeedback training, or relaxation techniques can be beneficial. Hypnosis has been used help sleepwalkers awaken once their feet touch the floor. Psychotherapy may help individuals who have underlying psychological issues that could be contributing to sleep problems.
Medications are sometimes used in the more severe cases with adults. Benzodiazepines—anti-anxiety drugs— such as diazepam (Valium) or alprazolam (Xanax) can be used to help relax muscles, although these may not result in fewer episodes of sleepwalking. When medications are used, they are typically prescribed in the lowest dose necessary and only for a limited period.
Most cases of sleepwalking subside over time. Sleepwalking in childhood usually disappears without treatment by age 15. If sleepwalking episodes persist into early adulthood, treatment is recommended. With an accurate diagnosis and appropriate treatment, episodes of sleepwalking can be greatly reduced and, in some cases, eliminated.
In children, sleepwalking is relatively common and is not cause for concern. The major risk associated with sleepwalking is accidental injury. Parents should take precautions to block stairways, lock windows, keep floors cleared of harmful objects, etc.
If taking certain medications, a medical condition, or exposure to significant stressors are suspected triggers of sleepwalking episodes, a doctor should be consulted for a complete assessment.
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American Academy of Sleep Medicine. 6301 Bandel Road NW, Suite 101, Rochester, MN 55901, (507) 287-6006 <http://www.assmnet.org/> .
American Psychiatric Association. 1400 K Street NW, Washington D.C. 20005. <http://www.psych.org> .
Better Sleep Council. 501 Wythe Street, Alexandria, VA 22314. (703) 683-8371. <http://www.bettersleep.org/> .
Health Communications.com. Sleep Channel. <http://www.sleepdisorderchannel.net/sleepwalking/index.shtml> .
Gary Gilles, M.A.