The cause of narcolepsy remains unknown. It is likely that it involves multiple factors interacting to cause neurological dysfunction and sleep disturbances.
(Click Cause of Narcolepsy for more information.)
What Are the Symptoms?Narcoleptic sleep episodes can occur at any time, and thus can 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 excessive and overwhelming daytime sleepiness, there are three other major symptoms that frequently characterize narcolepsy:
- Cataplexy, or the sudden loss of voluntary muscle tone
- Vivid hallucinations during sleep onset or upon awakening
- Brief episodes of total paralysis at the beginning or end of sleep.
Contrary to common belief, 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 experiencing 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.
(Click Narcolepsy Symptoms for more information.)