Frightening dreams or nightmares are far more frequent than night terrors and affect children and adults alike. They occur during periods of normal REM sleep and are particularly prominent during periods of increased REM sleep (REM rebound) following the withdrawal of alcohol or other sedative-hypnotic drugs that had suppressed REM sleep chronically. Autonomic changes are slight or absent, and the content of the dreams can usually be recalled in considerable detail. Some of these dreams (e.g., the ones occurring in the alcohol-withdrawal period) are so vivid that the patient may later have difficulty in separating them from reality; indeed, they may merge with the hallucinations of delirium tremens. Nightmares are of little significance as isolated events. Fevers dispose to them, as do conditions such as indigestion and the reading of bloodcurdling stories or exposure to terrifying movies or television programs before bedtime. Some patients report nightmares and extremely vivid dreams when first taking certain medications such as beta blockers and, particularly in our experience, l-dopa. We have also consulted on a few patients who complained of almost nightly nightmares and concurrent severe headaches, but without apparent depression or other psychiatric illness. Persistent nightmares may be a pressing medical complaint and are often accompanied by other behavioral disturbances or anxieties.
This condition occurs far more commonly in children (average age, 4 to 6 years) than in adults, and is often associated with nocturnal enuresis and night terrors, as indicated previously. It is estimated that 15 percent of children have at least one episode of sleepwalking, and that 1 in 5 sleepwalkers has a family history of this disorder. Motor performance and responsiveness during the sleepwalking incident vary considerably. The most common behavioral abnormality is for a patient to sit up in bed or on the edge of the bed without actually walking. When walking about the house, he may turn on a light or perform some other familiar act. There may be no outward show of emotion, or the patient may be frightened (night terror), but the frenzied, aggressive behavior of some adult sleepwalkers, described below, is rare in the child. Usually the eyes are open, and such sleepwalkers are guided by vision, thus avoiding familiar objects; the sight of an unfamiliar object may awaken them. Sometimes they make no attempt to avoid obstacles and may injure themselves. If spoken to, they make no response; if told to return to bed, they may do so, but more often they must be led back. Sometimes they repeatedly mutter strange phrases or perform certain repetitive acts, such as pushing against a wall or turning a doorknob back and forth. The episode lasts for only a few minutes, and the following morning, they usually have no memory of it, or only a fragmentary recollection.
A popular belief is that the sleepwalker is acting out a dream. The observations of sleep laboratories are entirely at variance with this view, as somnambulism has been found to occur almost exclusively during deeper stages of NREM sleep (stage N3) and during the first third of the night when dreaming is least likely to occur. In fact, the entire nocturnal sleep pattern of such individuals does not differ from normal. Also, there is no evidence that somnambulism is a form of epilepsy. It is probably allied to talking in one’s sleep, although the two conditions seldom occur together. Sleepwalking must be distinguished from fugue states and ambulatory automatisms of complex partial seizures discussed below and in Chap. 15.
The major consideration in the treatment of childhood somnambulism is to guard patients against injury by locking doors and windows, removing dangerous objects from the patients’ usual routes of march, having them sleep on the ground floor, etc. Children usually outgrow this disorder; parents should be reassured on this score and disabused of the notion that somnambulism is a sign of psychiatric or any other disease.