Narcolepsy is a chronic sleep disorder characterized by excessive sleepiness accompanied by a series of auxiliary symptoms, typically beginning in adolescence or young adulthood.

Narcolepsy is a sleep disorder. The principal symptoms are excessive daytime sleepiness (EDS) including sudden, brief (about 15 minutes) sleep attacks, cataplexy (sudden loss of muscle tone), hallucinations, that occur at the onset or offset (when starting to wake up) of sleep, and sleep paralysis.

Narcolepsy is believed...