Insomnia is more common in women than men, and increases with age.
Insomnia may encompass a variety of complaints such as difficulty falling asleep, frequent awakenings from sleep, a short sleep time, or even nonrestorative sleep. It can result from psychological factors, lifestyle factors, environmental factors, or physical illness. Of the more than 80 sleep disorders listed in the 1990 International Classification of Sleep Disorders, many can lead to a primary complaint of insomnia. Therefore, the optimal treatment of insomnia depends upon accurate diagnosis of the cause. Depression, anxiety, panic disorder, alcohol and drug abuse, and psychosis are all associated with insomnia.