Of all the sleep problems, disorders of initiating and maintaining sleep (insomnia) are the most common. Studies have shown that hypnotics are used regularly by about 25% of the adult population. Insomnia includes the following problems: delay in falling asleep, poor quality of sleep (deficiency of deep and rapid eye movement [REM] sleep), frequent awakening, and early-morning wakefulness. Because patients with insomnia may present complaining of trouble with sleeping, daytime sleepiness, or fatigue, the physician must be alert to all of these presenting complaints.
Insomnia may be chronic or transient. Chronic insomnia can be caused by physical disorders (e.g., congestive heart failure, pregnancy, hyperthyroidism, nocturnal asthma, nocturnal seizures), painful or uncomfortable syndromes (e.g., toothache, arthritis, restless legs syndrome), psychiatric illnesses (e.g., depression, anxiety, schizophrenia, mania), use or withdrawal of drugs (e.g., caffeine, alcohol, antidepressants, sympathomimetics, beta blockers, hypnotics), and situational stressors. The most common causes of chronic insomnia are ingestion of caffeine, alcohol consumption, sleep apnea, medical disorders, nocturia, anxiety, and depression. Transient insomnia is usually caused by stressful events, time zone shifts, and short-term pain-producing events.
Nocturnal enuresis (bed-wetting), sleepwalking, talking while asleep, and night terrors are thought to be arousal disorders because they usually occur with emergence from deep non-REM sleep. Children who experience nocturnal enuresis and sleepwalking often have difficulty sleeping. Bed-wetting is the most common sleep-arousal disorder in children between ages 3 and 15 years. It is more prevalent in males than females. When no obvious organic or psychological cause exists, bed-wetting usually occurs in the first part of the night as the child emerges from delta sleep and before the first REM sleep. The change of sleep state is often accompanied by body movements and increased muscle tone; urination occurs during this period. Although most of these problems have a psychological cause, many investigators believe that such disorders have a psychophysiologic rather than strictly psychological basis.
Nightmares and night terrors often disturb sleep. In both children and adults, nightmares occur during REM sleep. Night terrors, characterized by sudden screams and arousal, occur during deep sleep. Insomnia in children is most often caused by psychological stress but occasionally results from organic disease (e.g., hip disorder).
Some patients who snore have sleep-induced apnea, which causes nocturnal wakefulness and daytime drowsiness. These patients are typically obese and/or snorers. They may have as many as 100 episodes of sleep apnea each night; many episodes lead to brief arousal.
Too often, complaints of insomnia by the elderly are ignored as being part of the usual aging process. Sleep patterns often change with aging. Although some elderly people require less sleep than they did in their younger years, many complain of trouble sleeping. Elderly patients often complain of both a delay in falling asleep and poor sleep quality. They are more likely to awaken from environmental stimuli such as noise and temperature and often have associated medical or painful conditions that interfere with the quality of sleep.
Many patients who ingest products that contain caffeine (e.g., coffee, tea, cola) complain of insomnia. Even those patients who had previously tolerated caffeine well may experience sleeping problems. Because the half-life of caffeine may range from 2 to more than 6 hours in different people, the ingestion of caffeine, especially after 6 PM, may contribute significantly to insomnia. Patients may or may not be aware that caffeine is the cause of their insomnia. People who drink alcohol, even in moderate amounts (i.e., two drinks at night), as well as recovering alcoholics often experience poor sleep quality with frequent awakening.
Poor sleep at night may be related to napping or dozing during the day, which is more common in elderly people. Elderly patients with dementia are often restless and wakeful at night. Depression, a common cause of sleep disturbances, is frequently undiagnosed in elderly patients.
Patients of all ages with depression (unipolar affective disorder) frequently experience insomnia characterized by delayed sleep onset (prolonged latency), frequent awakening, and classic early-morning wakefulness. Young adults without apparent depression who have insomnia have a higher incidence of depression in later life. Patients with bipolar affective disorder may experience marked insomnia, especially just before and during the manic phase. Patients who suffer from anxiety may have trouble falling asleep but seldom experience early-morning wakefulness.