Insomnia

Overview

Insomnia is a symptom with diverse etiologies. It occurs when a person has trouble falling or staying asleep, wakes up too early and cannot return to sleep, or does not feel refreshed after sleeping.

Insomnia is classified as transient, short term, or chronic according to the duration of sleep disturbance. Transient insomnia often is self-limiting, lasting less than 1 week. Short-term insomnia usually lasts from 1 to 3 weeks. Chronic insomnia persists >3 weeks and often is the result of medical problems, psychiatric disorders, or substance abuse. Nonprescription sleep aids generally are not helpful in patients with chronic insomnia; medical referral is indicated.

Patients with sleep disorders such as sleep apnea, narcolepsy, or restless legs syndrome may seek nonprescription sleep aids. Because of potentially significant adverse clinical effects, patients with these disorders preferably should see a sleep specialist.

Epidemiology

Insomnia is one of the most common patient complaints, ranking third behind headache and the common cold.
Although the average adult requires ≥8 hours of sleep nightly, the typical American gets 6.9 hours.
An estimated 33% of the U.S. population experiences insomnia nightly.
To manage insomnia, about 11% of adult Americans report using alcohol; 9% use a nonprescription sleep aid; and 7% use a prescription hypnotic medication.
The prevalence of sleep complaints and hypnotic use is high among persons of advanced age. More than half of this population reports at least one sleep complaint.

Etiology

Difficulty falling asleep often is associated with acute life stresses or medical illness, anxiety, or poor sleep habits.
The severity of stressful situations can affect the length of insomnia.
- Travel, hospitalization, or anticipation of an important or stressful event can cause transient insomnia.
- If more severe stressors are present (e.g., the death of a loved one, recovery from surgery, the loss of a job, or divorce), transient insomnia can become short-term insomnia.
Late-night exercise and late-evening meals as well as environmental distractions (e.g., noise, lighting, uncomfortable temperatures, and new surroundings) can interfere with sleep.
Some individuals are extremely sensitive to the stimulant effects of caffeine and nicotine. Drinking caffeinated beverages in the late afternoon or evening hours can cause insomnia.
Alcohol can cause insomnia after acute use and as a withdrawal effect after chronic use.
A number of general medical disorders and psychiatric disorders are associated with chronic insomnia (see Table 1).
Prescription and nonprescription medications can produce either insomnia or withdrawal insomnia.
- Antidepressants, antihypertensives, and sympathomimetic amines commonly are associated with causing insomnia.
Shift workers often complain of sleep disturbances and/or excessive sleepiness. Sleep problems occur more frequently in individuals who must rotate shifts.
Children and adolescents may present with insomnia because of a circadian rhythm disorder.
Patients who have sleep difficulty that lasts at least 1 month; affects psychosocial functioning; and is not caused by another sleep disorder, general medical disorder, psychiatric disorder, or medication are said to have primary insomnia.