Section 6. Brain, Spinal Cord, and Nerve Disorders

Chapter 81. Sleep Disorders

Topics: Introduction | Insomnia | Hypersomnia | Narcolepsy | Sleep Apnea Syndromes | Parasomnias | Sleep Disorders in People With Dementia

Insomnia

Insomnia is difficulty falling asleep or staying asleep or a disturbance in sleep that makes sleep seem inadequate or unrefreshing.

Insomnia is not a disease. It is a symptom that can have many different causes, including an irregular sleep-wake schedule, physical disorders, drug use or withdrawal, drinking large amounts of alcohol in the evening, emotional problems, and stress. Often, the cause is anxiety, nervousness, depression, or fear. Sometimes the cause is simply lack of fatigue. Some people have long-standing (chronic) insomnia that has little or no apparent relationship to a physical disorder, use or withdrawal of drugs, or any stress.

Difficulty falling asleep is common among young and old. About 10% of adults have chronic insomnia, and about 50% have insomnia sometimes.

Because sleep patterns change as people age, older people may think they have insomnia when they do not. As people age, they tend to sleep less at night and to nap during the day. Stage 4 sleep, the period of deep sleep, becomes shorter and eventually disappears. Also, older people awaken more during all stages of sleep. These changes are normal and usually do not indicate a sleep disorder.

There are several types of insomnia. Difficulty falling asleep, called sleep-onset insomnia, often occurs when people cannot let their minds relax and they continue to think and worry. Difficulty staying asleep, called sleep maintenance insomnia, is more common among older people than among younger people. People with this type of insomnia fall asleep normally but wake up several hours later and cannot fall asleep again easily. Sometimes they drift in and out of a restless, unsatisfactory sleep. Early morning awakening, another type of insomnia, may be a sign of depression in people of any age.

Sleep-wake schedule disorder may occur in people whose sleep patterns have been disrupted: They fall asleep at inappropriate times and then cannot sleep when they should. These sleep-wake reversals often result from jet lag (especially when traveling from east to west), working irregular night shifts, frequent changes in work hours, or excessive use of alcohol. Sometimes sleep-wake reversals are a side effect of drugs. Sleep-wake reversals are common among people who are hospitalized because they are often awakened during the night. Damage to the brain's built-in biologic clock (caused by encephalitis, stroke, or Alzheimer's disease, for example) can also disrupt sleep patterns.

Symptoms and Diagnosis

Symptoms include irritability, fatigue during the day, and problems concentrating or performing under stress.

To diagnose insomnia, doctors evaluate a person's sleep pattern, use of drugs (including alcohol and illicit drugs), degree of psychologic stress, medical history, and level of physical activity. Some people need less sleep than others, so the diagnosis of insomnia is based on a person's individual needs.

Treatment

The treatment of insomnia depends on its cause and severity. If insomnia results from another disorder, treatment of that disorder may improve sleep. For most people who have insomnia, some simple changes in lifestyle, such as following a regular sleep schedule, can improve sleep.

Bright light therapy (which exposes a person to bright light at appropriate times) can help reset the biologic clock. This therapy is especially useful for people who have sleep-wake reversal due to jet lag, those who have sleep-onset insomnia, and those who go to sleep and wake too early.

When a sleep disorder interferes with a person's normal activities and sense of wellbeing, the intermittent use of sleep aids (also called hypnotics) for up to a week may be helpful. Most sleep aids require a prescription. Sleep aids available without a prescription (over-the-counter, or OTC (see Section 2, Chapter 18)) contain diphenhydramine or doxylamine, both antihistamines. These drugs may have side effects, especially in older people.

Older people experiencing age-related sleep changes usually do not need to take sleep aids. Because total nighttime sleeping time tends to decrease with age, older people may sleep better if they go to bed later, get up earlier, or nap less during the day. Even when older people have insomnia, treatment with sleep aids often causes more problems (such as confusion, falls, and incontinence) than the insomnia.

If emotional stress is causing insomnia, treatment to relieve the stress is more useful than taking sleep aids. People who have insomnia and depression should be evaluated by a doctor, and the depression should be treated. Treating depression often relieves the insomnia, but some antidepressants can improve sleep directly because they have sedating effects.

Melatonin (see Section 2, Chapter 19) is sometimes used to treat insomnia, especially in older people, who may have low levels of melatonin. The drug is also sometimes used to help minimize the effects of jet lag. However, its use is controversial. Melatonin appears to be safe for short-term use (up to a few weeks), but the effects of using it for a long time are unknown.

See the sidebar Ways to Improve Sleep.

See the sidebar Sleep Aids: Not to Be Taken Lightly.