(n) a chronic
and usually hereditary
sleep disorder in which the person affected will suffer spontaneous bouts of sleep (or "sleep attacks") during the day. Symptoms include: extreme sleepiness, typically followed by sleep attacks and last for fifteen minutes; dream-like hallucinations; sleep paralysis
, where you cannot move when you start to fall asleep or just after you wake up; and cataplexy
, which is an abrupt loss of muscle tone (basically, your muscles "fail you
The disorder is not fatal
, but can be depending on the situation you find yourself having a sleep episode. There is no cure for narcolepsy at the moment.
For more detailed information on narcolepsy, visit a medical site.