[Narcolepsy].

Narcolepsy is a rather unknown but not exceptional condition. Its prevalence, 2 to 6/10000, is ranging among this of multiple sclerosis. Narcolepsy is remarkable for clinical, polygraphic and immunogenetic features which make it a kind of model of disorders of alertness. It was first described in 1877. It has recently benefited from consistent pathophysiological progresses, which have been facilitated by the discovery of a natural canine model. The two main symptoms are irresistible and refreshing episodes of sleep and cataplexy a loss of muscle tone emotionally triggered. Polygraphically the sleep onset REM period is the major feature. Immunogenetically the condition is remarkable for an almost 100% association with HLA DR2-DQ1. Narcolepsy is a debilitating, chronic condition. Its treatment is threefold including stimulants against excessive daytime sleepiness and irresistible episodes of sleep, modafinil a new compound with awakening properties has just been introduced, antidepressants against cataplexy and associated symptoms and hypnotics against disrupted sleep.