Testing the Reliability and Validity of DSM-IV-TR and ICSD-2 Insomnia Diagnoses: Results of a Multitrait-Multimethod Analysis

Context Distinctive diagnostic classification schemes for insomnia diagnoses are available, but the optimal insomnia nosology has yet to be determined. Objectives To test the reliability and validity of insomnia diagnoses listed in the American Psychiatric Association's DSM-IV-TR and the International Classification of Sleep Disorders, second edition (ICSD-2). Design Multitrait-multimethod correlation design. Setting Two collaborating university medical centers, with recruitment from January 2004 to February 2009. Participants A total of 352 adult volunteers (235 of whom were women) who met research diagnostic criteria for insomnia disorder. Main Outcome Measures Goodness-of-fit ratings of 10 DSM-IV-TR and 37 ICSD-2 insomnia diagnoses for each patient. Ratings were provided by 3 clinician pairs who used distinctive assessment methods to derive diagnostic impressions. Correlations computed within and across clinician pairs were used to test reliability and validity of diagnoses. Results Findings suggested that the best-supported DSM-IV-TR insomnia categories were insomnia related to another mental disorder, insomnia due to a general medical condition, breathing-related sleep disorder, and circadian rhythm sleep disorder. The category of primary insomnia appeared to have marginal reliability and validity. The best-supported ICSD-2 categories were the insomnias due to a mental disorder and due to a medical condition, obstructive sleep apnea, restless legs syndrome, idiopathic insomnia, and circadian rhythm sleep disorder–delayed sleep phase type. Psychophysiological insomnia and inadequate sleep hygiene received much more variable support across sites, whereas the diagnosis of paradoxical insomnia was poorly supported. Conclusions Both the DSM-IV-TR and ICSD-2 provide viable insomnia diagnoses, but findings support selected subtypes from each of the 2 nosologies. Nonetheless, findings regarding the frequently used DSM-IV-TR diagnosis of primary insomnia and its related ICSD-2 subtypes suggest that their poor reliability and validity are perhaps due to significant overlap with comorbid insomnia subtypes. Therefore, alternate diagnostic paradigms should be considered for insomnia classification.