Self Help

Narcolepsy is found in about 6 out of every 1000 people in the world. It has been estimated that in the United States about 250,000 people have this type of sleep disorder.

The exact cause of narcolepsy (chronic daytime sleepiness) is not fully understood, although there is a strong genetic factor linked to the disorder. Relatives of patients with narcolepsy are at a much greater risk for developing the disorder.

Narcolepsy commonly begins sometime between early teenage years and young adulthood. The first symptom to appear is the irresistible daytime sleepiness. Other symptoms may not appear until several years later. Other symptoms such as cataplexy, sleep paralysis, and hypnagogic hallucinations are the result of a partial activation of REM sleep while the person is still awake.

Cataplexy is very much like the paralysis experienced during REM sleep. The difference is that this partial activation of REM sleep during cataplexy involuntarily intrudes on wakefulness. The brain waves during a cataplectic attack reveal a pattern suggesting wakefulness.

Sleep paralysis is similar to cataplexy, although the patient with narcolepsy is usually in bed. Hypnagogic hallucinations can be viewed as manifestations of REM sleep. It is as if while lying in bed, a dream inappropriately begins while the person is still conscious.

Patients with narcolepsy tend to have “lighter” sleep at night and wake up more frequently than most individuals. They also tend to have excessive periodic limb movements during sleep. However, these phenomena don’t altogether explain the severe daytime sleepiness seen in narcolepsy. Some patients with narcolepsy get plenty of good quality sleep at night and still find themselves very sleepy during the day.

Narcolepsy is often viewed as a disorder of rapid eye movement (REM) sleep or as an imbalance between the physiologic mechanisms that control sleep and wake. When we fall asleep at night, most of us go directly into non-rapid eye movement (NREM) sleep. After approximately an hour and a half of NREM sleep, we then enter REM sleep. On the other hand, patients with narcolepsy often enter REM sleep as soon as they fall asleep, that is, they have sleep onset REM periods.

When patients with narcolepsy fall asleep unintentionally during the day, they also may enter REM sleep right away. This is why narcolepsy is considered a disorder of REM sleep. However, patients with narcolepsy do not always enter REM sleep immediately. They may enter NREM sleep first, just as most of us do.