In severe cases, narcolepsy symptoms can cause serious disruptions in a person's social, personal, and professional life. The classic symptom is excessive and overwhelming daytime sleepiness. Other symptoms of narcolepsy include cataplexy, sleep paralysis, and hypnagogic hallucinations. In most cases, the first symptom to appear is excessive and overwhelming daytime sleepiness.
Narcolepsy is a chronic condition caused by the brain's inability to regulate sleep-wake cycles normally. At various times throughout the day, people with narcolepsy experience the fleeting urge to sleep. If the urge becomes overwhelming, people fall asleep for periods lasting from a few seconds to several minutes. In rare cases, some people may remain asleep for an hour or longer.
The classic narcolepsy symptom is excessive and overwhelming daytime sleepiness. Three other classic symptoms, which may not occur in all people, are:
- Sleep paralysis
- Hypnagogic hallucinations.
Excessive Daytime Sleepiness
The characteristic symptom of narcolepsy is excessive and overwhelming daytime sleepiness, even after adequate nighttime sleep. A person with narcolepsy is likely to become drowsy or to fall asleep, often at inappropriate times and places. Daytime sleep attacks may occur with or without warning and may be irresistible. These attacks can occur repeatedly in a single day. Drowsiness may persist for prolonged periods of time. In addition, nighttime sleep may be fragmented, with frequent interruptions.
Cataplexy is another symptom of narcolepsy. This is a sudden episode of loss of muscle function, ranging from slight weakness (such as limpness at the neck or knees, sagging facial muscles, or inability to speak clearly) to complete body collapse. Attacks may be triggered by sudden emotional reactions, such as laughter, anger, or fear, and may last from a few seconds to several minutes. The person remains conscious throughout the episode.