People who have narcolepsy experience such overwhelming daytime sleepiness— even after adequate sleep at night—that they become drowsy or fall asleep at inappropriate times and places during the day. Such “sleep attacks” can occur repeatedly during a given day and may come on without warning. Another classic symptom of narcolepsy is cataplexy (sudden episodes of loss of muscle function that cause the person to collapse suddenly or his or her neck to go limp). Sleep paralysis often occurs, preventing the affected person from moving while falling asleep or waking up. Some people also have vivid hallucinations while falling asleep. Such symptoms can seriously disrupt the person’s life and limit his or her activities.

Narcolepsy occurs in both men and women and can begin at any age. As many as 200,000 people are affected, although the problem is often underdiagnosed or misdiagnosed as depression, epilepsy, or side effects of medication. Doctors think that a disturbance in the normal order of sleep stages causes narcolepsy. Most people first go through a stage of nonrapid eye movement (NREM) when falling asleep, followed by a stage of rapid eye movement (REM), when dreaming and muscle relaxation occur. In people with narcolepsy, these stages are reversed.
To diagnose narcolepsy, doctors perform two tests—polysomnography and the multiple sleep latency test—at a sleep center or at the person’s home.
There is no cure for narcolepsy, but certain treatments can relieve symptoms. Drugs called central nervous system stimulants (such as methylphenidate, dextroamphetamine, or modafinil) can help manage the excessive daytime sleepiness caused by narcolepsy. Antidepressants (such as amitriptyline or fluoxetine) also are prescribed. An important part of treatment is scheduling short naps two to three times per day to help relieve daytime sleepiness. Some people with narcolepsy and their families find it helpful to join a support group where they can learn to deal with the emotional effects of the disorder, talk about occupational limitations, and find out how to avoid situations that could cause injury.