ABSTRACT

The International Classification of Sleep Disorders (ICSD-2) (1) recognizes a vast differential of etiologies of hypersomnolence. Those types of hypersomnolence with a cause of central origin are the focus in this section (Table 1); those due to sleep-related breathing disorders, circadian rhythm sleep disorders, or other causes of disturbed sleep are discussed separately. The main groups of central origin hypersomnias include narcolepsy, recurrent hypersomnia (including Kleine-Levin syndrome and menstrual-related hypersomnia), idiopathic hypersomnia, behaviorally induced insufficient sleep syndrome, hypersomnia due to medical conditions or drugs, nonorganic hypersomnia, and unspecified physiological hypersomnia.