ABSTRACT

Circadian rhythm sleep disorders (CRSDs) are a family of sleep disorders affecting the timing of sleep. They result from a mismatch between the body’s endogenous clock and external timing cues provided by an individual’s 24-hour schedule. People with CRSDs typically cannot sleep or wake at the times required for work, school, or other social routines, but can generally get enough sleep if allowed to sleep and wake at preferred times. CRSDs diagnoses include delayed sleep phase type (DSPT), advanced sleep phase type (ASPT), irregular sleepwake type, free-running type, jet lag type, shift work type, and CRSD due to medical conditions. This chapter will briefly describe each disorder, its etiology, pathophysiology, and pathogenesis; predisposing and precipitating factors; associated morbidity and mortality; and associations, complications, and consequences.