An exhaustive triaxial classification manual related to the ICD-9-CM classifications of procedures and diseases: Axis A is the International Classification of Sleep Disorders (ICSD) categorizations (which make up the body of this manual); B and C are the ICD-9-CM procedure and disease (non-sleep disorder diagnoses) classifications. The ICSD diagnostic articles include synonyms and keywords, essential and associated features, course, predisposing factors, prevalence, age of onset, sex ratio, familial pattern, pathology, complications, Polysomnographic features, differential diagnosis, diagnostic criteria, minimal criteria, severity criteria, duration criteria, and a bibliography. The disorders represented run through the full spectrum of sleep difficulties, including, for example,