Narcolepsy
Etiology
Symptoms
Narcolepsy is diagnosed when an individual has repeated sudden occurrences of sleep for a period of at least three months. To be diagnosed, at least one of the following must be present: cataplexy (brief episodes of sudden loss of muscle tone) and REM intrusions (REM sleep occurs at unexpected times and results in hallucinations or sleep paralysis). These symptoms can not be the result of another mental disorder, a medical condition, or the use of substances.