Narcolepsy is a chronic neurological disorder caused by the brain’s inability to regulate sleep-wake cycles normally. At various times throughout the day, a person with narcolepsy experience fleeting urges to sleep. If the urge becomes overwhelming, patients 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.
Narcoleptic sleep episodes can occur at any time, and thus frequently prove profoundly disabling. People may involuntarily fall asleep while at work or at school, when having a conversation, playing a game, eating a meal, or most dangerously, when driving an automobile, or operating other types of potentially hazardous machinery. In addition to daytime sleepiness, three other major symptoms frequently characterize narcolepsy: cataplexy, or the sudden loss of voluntary muscle tone; vivid hallucinations during sleep onset or upon awakening; and brief episodes of total paralysis at the beginning or end of sleep.
Contrary to common beliefs, people with narcolepsy do not spend a substantially greater proportion of their time asleep during a 24 hour period than do normal sleepers. In addition to daytime drowsiness and involuntary sleep episodes, most patients also experience frequent awakenings during nighttime sleep. For these reasons, narcolepsy is considered to be a disorder of the normal boundaries between the sleeping and waking states.
