Disorders of Excessive Somnolence

**Definition:** Disorders characterized by hypersomnolence during normal waking hours that may impair cognitive functioning. Subtypes include primary hypersomnia disorders (e.g., IDIOPATHIC HYPERSOMNOLENCE; NARCOLEPSY; and KLEINE-LEVIN SYNDROME) and secondary hypersomnia disorders where excessive somnolence can be attributed to a known cause (e.g., drug affect, MENTAL DISORDERS, and SLEEP APNEA SYNDROME). (From J Neurol Sci 1998 Jan 8;153(2):192-202; Thorpy, Principles and Practice of Sleep Medicine, 2nd ed, p320)

**Tree numbers:** - C10.886.425.800.200 - F03.870.400.800.200

**Synonyms:** - Hypersomnolence Disorders - DOES (Disorders of Excessive Somnolence) - Excessive Somnolence Disorders