Medical Terminology

International Classification of Sleep Disorders (ICSD)

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The International Classification of Sleep Disorders (ICSD) is the authoritative clinical text for the diagnosis of sleep disorders, published by the American Academy of Sleep Medicine. The 3rd edition, ICSD-3, was published in 2014, replacing ICSD-2 (which had replaced ICSD-1 in 2005).

The ICSD-3 groups sleep disorders into six major categories – 1) insomnia, 2) sleep-related breathing disorders, 3) central disorders of hypersomnolence, 4) circadian rhythm sleep-wake disorders, 5) parasomnias, and 6) sleep-related movement disorders. A seventh category is for “other sleep disorders” not captured by the six major categories. Sleep disorders including idiopathic hypersomnia, narcolepsy (both types 1 and 2), and Kleine-Levin syndrome are categorized as “central disorders of hypersomnolence.”

For an overview of current diagnosis methods, see our Classification of Hypersomnias web page. For the ICSD-3’s diagnostic criteria for idiopathic hypersomnia, see our IH Summary.


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