Overview of Hypersomnias

Excessive sleepiness is characterized by an increased amount of sleep or an increased drive toward sleep during the wake period that makes a person unable to sustain wakefulness or alertness in situations where it is required. Hypersomnias are disorders that cause excessive sleepiness by either fragmenting nocturnal sleep (e.g., obstructive sleep apnea and periodic limb movement disorder), shortening the major sleep period (e.g., behaviorally induced insufficient sleep syndrome), or are the result of central nervous system pathology (e.g., narcolepsy). This article highlights the key symptoms, diagnostic criteria, epidemiology, pathophysiology, and treatment for the hypersomnias of central origin.