ABSTRACT
This chapter provides recommendations for the clinical diagnosis of circadian rhythm sleep disorders (CRSDs). The International Classification of Sleep Disorders, second edition (ICSD-2) (1) lists nine types of CRSDs, all of which meet the following general criteria: (i) the sleep disturbance is primarily due to a mismatch between the internal biological clock and the environment; (ii) the disorder involves complaints of insomnia, excessive daytime sleepiness, or both; and (iii) the sleep disruption is associated with impaired daytime functioning in multiple areas, such as academic, occupational, social, and family performance.
