Narcolepsy is a disorder caused by the brain's inability to regulate sleep-wake cycles. The primary characteristics of narcolepsy are excessive daytime sleepiness and cataplexy (sudden loss of muscle tone). The disease is also often associated with sudden sleep attacks, insomnia, dream-like hallucinations, and a condition called sleep paralysis.
Despite the perception that people with narcolepsy are perpetually sleepy, they do not typically sleep more than the average person. This disease affects both sexes equally and develops with age; symptoms usually first appear in adolescence or young adulthood and may remain unrecognized as they gradually develop.
Narcolepsy patients typically endure many years of daytime sleepiness before seeking treatment because sleepiness is not indicative of disease to most people. Yet the devastating potential of this disorder is reflected in studies showing that narcoleptic patients are more accident-prone and may have difficulty with interpersonal relationships.