Résumé
Besides obstructive sleep apnea syndrome and narcolepsy, there are a number of other causes of excessive daytime sleepiness, listed in the International Classification of Sleep Disorders, third edition, as central disorders of hypersomnolence. They include primary sleep disorders such as idiopathic hypersomnia, KleineLevin syndrome and a number of hypersomnias due to a medical disorder, a medication, or a substance, associated with a psychiatric disorder, or due to insufficient sleep. Idiopathic hypersomnia and Kleine–Levin syndrome have attracted much interest in recent years, and an overview of recent progresses is presented in this chapter. The symptomatic hypersomnias are less well known to sleep physicians and often neglected by specialists, either internists or psychiatrists, although they may seriously impact the quality of life of patients