Narcolepsy (pronounced NAR-ko-lep-see) is a disorder that causes a person to have difficulty staying awake. Narcolepsy can cause a person to suddenly fall asleep during the day. These "sleep attacks" occur even after getting enough sleep at night. The unusual and unpredictable sleep pattern that people with narcolepsy have can affect their schooling, work and social life.

The symptoms of narcolepsy can appear all at once, or they can develop slowly over many years. The four most common symptoms are:

  • excessive daytime sleepiness;
  • cataplexy, which is a sudden, brief loss of muscle control triggered by stress or strong emotion;
  • sleep paralysis, or the temporary inability to move either when falling asleep or awakening;
  • hypnagogic hallucinations, which are vivid, dream-like experiences that are difficult to distinguish from reality and occur at sleep onset or after awakening.

Narcolepsy is usually diagnosed by a medical history and an overnight sleep study. The next day following a sleep study, a multiple sleep latency test will also be done to determine daytime sleepiness.

Narcolepsy cannot be cured, but its symptoms can usually be controlled so that a person with narcolepsy can lead a normal life. Each treatment plan usually involves medication, life-style changes, and education.