Glossary

International Classification of Sleep Disorders [ICSD]

The International Classification of Sleep Disorders (ICSD) is a reference book that helps doctors figure out if someone has a sleep disorder. It’s published by the American Academy of Sleep Medicine (AASM) and updated as researchers learn more about sleep disorders. The most recent version is 2023’s ICSD-3-TR (text revision).

The ICSD-3-TR puts sleep disorders into these groups:

• Insomnia
• Sleep-related breathing disorders
• Central disorders of hypersomnolence (CDH)
• Circadian rhythm sleep-wake disorders
• Parasomnias
• Sleep-related movement disorders
• Other sleep disorders

The CDH are also called hypersomnia disorders, or hypersomnias. They include:

• Idiopathic hypersomnia
• Narcolepsy types 1 and 2
• Kleine-Levin syndrome
• Hypersomnia and narcolepsy associated with other disorders

To learn more about how doctors figure out if someone has a sleep disorder, see our web page “Diagnosis, classification, symptoms, and causes of hypersomnias.”