Parasomnias

Parasomnias are unusual behaviors that occur during sleep.

Various unconscious and largely unremembered behaviors can occur during sleep, more often in children than in adults. Just before falling asleep, almost all people occasionally experience brief, involuntary jerks of the arms or the entire body. Occasionally, the legs jerk. Some people also experience sleep paralysis (attempting but being unable to move) or brief hallucinations when they are just falling asleep or awakening. People may clench or grind their teeth or have nightmares. Sleepwalking, head-banging, and night terrors are more common among children and can be very distressing for their parents. Usually, the children do not remember these episodes.

Restless legs syndrome is a relatively common disorder, probably affecting 1 to 5% of people. It is particularly common among people older than 50. The cause is unknown, but one third or more of people with the syndrome have family members with the syndrome. Risk factors include a sedentary lifestyle, smoking, and obesity. Use of alcohol, caffeine, and many drugs (mostly antidepressants) worsens the syndrome, as do iron deficiency and pregnancy.

Typically, people with restless leg syndrome feel vague but intense crawling sensations in their legs and have an urge to move their legs when sitting still or when lying in bed before falling asleep. Walking or moving the legs can relieve the sensations. During sleep, the legs move spontaneously and uncontrollably, often awakening the sleeper. Symptoms are more likely to occur when people are under stress. The resulting sleep loss and distress may be extreme.

Benzodiazepine drugs (such as clonazepam in low doses), taken at bedtime, sometimes relieve the symptoms of restless legs syndrome. People with severe symptoms may benefit from drugs used to treat Parkinson's disease, such as pergolide, levodopa-carbidopa, or pramipexole (see Section 6, Chapter 91). The opioid oxycodone or the anticonvulsants gabapentin or carbamazepine (see Section 6, Chapter 85) are effective in some people.

Night terrors are frightening episodes during which a person sits up, screams, and flails about. The eyes are wide open, and the heart races. Episodes usually occur during non-REM stages of sleep. Night terrors are more common among children. Children should not be awakened. They usually stop having episodes when they become older. Episodes in adults are often associated with psychologic problems or alcoholism. Treatment with certain benzodiazepines, such as clonazepam, or tricyclic antidepressants, such as imipramine, may be helpful.

Nightmares are vivid, frightening dreams, followed by sudden awakening. Children and adults can have nightmares. Nightmares occur during REM sleep. They are more likely to occur when a person is under stress, has a fever, is excessively tired, or has consumed alcohol. Treatment, if necessary, focuses on the underlying problem.

Sleepwalking (somnambulism), most common in late childhood and adolescence, is walking in a semiconscious manner without being aware of it. It occurs during the deepest stages of sleep. People do not dream while sleepwalking--in fact, brain activity during sleepwalking, although abnormal, is more like that of a wakeful state than of a sleeping one. Sleepwalkers may mumble repetitiously and can hurt themselves by walking into obstacles. Most sleepwalkers have no memory of sleepwalking.

No specific treatment is available, but the sleepwalker can be gently led back to bed. Leaving a light on in the bedroom or adjacent hall sometimes reduces the tendency to sleepwalk. Forcibly awakening the sleepwalker may provoke an angry reaction and is not advised. Obstacles or breakable objects in the sleepwalker's potential path should be removed, and windows should be kept closed and locked. Benzodiazepines, particularly diazepam and alprazolam, may help. Selective serotonin reuptake inhibitors (SSRIs) (see Section 7, Chapter 101) may be used if benzodiazepines are ineffective.