Sleep Disorders

Narcolepsy

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

If not treated, people with narcolepsy can fall asleep at any time, such as when at work, while driving and while engaged in a conversation. Narcolepsy is linked to a chemical in the brain called hypocretin, which normally stimulates arousal and helps regulate sleep. Most people with narcolepsy do not produce hypocretin in the deep part of the brain called the hypothalamus. As a result, the body's messages about when to sleep and when to stay awake sometimes occur at the wrong times and places.

Narcolepsy is a lifelong condition that affects an estimated one in 1,000 to 1,5000 people. Although it occurs in both men and women, it is slightly more common among men. The condition can begin at any age, although its symptoms usually appear between the ages of 10 and 20. Narcolepsy has been found to be heredity in some cases.

Symptoms

The hallmark symptom of narcolepsy is an excessive daytime sleepiness (EDS), in which a person falls asleep at times when they want to be awake. EDS may include daytime sleep attacks that occur with or without warning, persistent drowsiness and fleeting moments of sleep that occur in between a person's waking state.

Other symptoms may include:

• Cataplexy -- Most people with narcolepsy experience some degree of cataplexy, which is defined as a sudden loss of voluntary muscle control. An attack may involve only a slight feeling of weakness and limp muscles -- such as sagging facial muscles, nodding head, buckling knees, loss of arm strength and garbled speech -- or also may cause immediate total body collapse. These attacks are usually triggered by intense emotions, such as laughter, surprise, anger, stress and fear, and can last anywhere from a few seconds to thirty minutes.

• Sleep Paralysis -- For a brief period when falling asleep or waking up, a person with narcolepsy may be unable to talk or move.

• Hypnagogic Hallucinations -- These are defined as vivid, realistic and typically frightening dreams that occur when a person is falling asleep.

• Automatic Behavior -- This occurs when familiar or routine tasks -- such as making coffee in the morning, getting the paper and taking a shower -- are performed without full memory or awareness of them.

• Fragmented Nighttime Sleep -- In addition to having trouble with sleep during the day, people with narcolepsy also tend to sleep poorly at night, waking up often.

Reviewed by health care specialists at UCSF Medical Center.
Last updated November 4, 2007