Classification of sleep disorders

The classification of sleep disorders has been of particular interest to clinicians ever since they were initially recognized. The International Classification of Sleep Disorders, 2nd edn (ICSD-2) classification lists 85 sleep disorders, each presented in detail and with a descriptive diagnostic text that includes specific diagnostic criteria. The ICSD-2 has eight major categories: (1) the insomnias; (2) the sleep-related breathing disorders; (3) the hypersomnias not due to a sleep-related breathing disorder; (4) the circadian rhythm sleep disorders; (5) the parasomnias; (6) the sleep-related movement disorders; (7) other sleep disorders; and (8) isolated symptoms, apparently normal variants, and unresolved issues (Table 1.1).