Background: Although several diagnostic systems define insomnia, little is known about the implications of using one versus another of them.
Methods: The America Insomnia Survey, an epidemiological survey of managed health care plan subscribers (n = 10,094), assessed insomnia with the Brief Insomnia Questionnaire, a clinically validated scale generating diagnoses according to DSM-IV-TR; International Statistical Classification of Diseases, Tenth Revision (ICD-10); and Research Diagnostic Criteria/International Classification of Sleep Disorders, Second Edition (RDC/ICSD-2) criteria. Regression analysis examines associations of insomnia according to the different systems with summary 12-item Short-Form Health Survey scales of perceived health and health utility.
Results: Insomnia prevalence estimates varied widely, from 22.1% for DSM-IV-TR to 3.9% for ICD-10 criteria. Although ICD insomnia was associated with significantly worse perceived health than DSM or RDC/ICSD insomnia, DSM-only cases also had significant decrements in perceived health. Because of its low prevalence, 66% of the population-level health disutility associated with overall insomnia and 84% of clinically relevant cases of overall insomnia were missed by ICD criteria.
Conclusions: Insomnia is highly prevalent and associated with substantial decrements in perceived health. Although ICD criteria define a narrower and more severe subset of cases than DSM criteria, the fact that most health disutility associated with insomnia is missed by ICD criteria, while RDC/ICSD-only cases do not have significant decrements in perceived health, supports use of the broader DSM criteria.
Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.