Sleep disorders have been included in the Diagnostic and Statistical Manual of Mental Disorders since 1987. DSM-III-R (American Psychiatric Association 1987) classified patients first according to their primary complaint of “dyssomnia” (including insomnia, hypersomnia, and circadian rhythm disorder) or “parasomnia.” The DSM-III-R sleep disorder system was the first psychiatric sleep classification to demonstrated diagnostic interrater reliability by the use of a structured interview (Schramm et al. 1993). In DSM-IV (American Psychiatric Association 1994), patients are classified at the first level by presumed pathophysiology rather than by presenting symptom.

Thus, DSM-IV includes major sections of primary sleep disorders, sleep disorders related to another mental disorder, secondary sleep disorders due to an Axis III condition, and substance-induced sleep disorders (

Table 89-1). The number of specific sleep diagnoses in DSM-IV is greater than that in DSM-III-R but far smaller than that in the International Classification of Sleep Disorders (ICSD), the classification used by most sleep specialists (Diagnostic Classification Steering Committee 1990). DSM-IV sleep disorders characterized by insomnia have moderately good interrater reliability in clinical practice, with mean kappa values in the range of 0.30-0.57 (Buysse et al. 1994). Specific diagnoses have also been shown to result in different treatment recommendations (Buysse et al. 1997b).