Days-out-of-role associated with insomnia and comorbid conditions in the America Insomnia Survey

Biol Psychiatry. 2011 Dec 1;70(11):1063-73. doi: 10.1016/j.biopsych.2011.08.010. Epub 2011 Oct 1.


Background: Insomnia is highly prevalent and impairing but also highly comorbid with other chronic physical/mental disorders. Population-based research has yet to differentiate the role impairments uniquely associated with insomnia per se from those due to comorbidity.

Methods: A representative sample of 6791 adult subscribers to a large national US commercial health plan was surveyed by telephone about sleep and health. Twenty-one conditions previously found to be comorbid with insomnia were assessed with medical/pharmacy claims data and validated self-report scales. The Brief Insomnia Questionnaire, a fully structured, clinically validated scale, generated insomnia diagnoses according to inclusion criteria of DSM-IV-TR, ICD-10, and Research Diagnostic Criteria/International Classification of Sleep Disorders: Diagnostic and Coding Manual, Second Edition. The World Health Organization Disability Assessment Schedule-II assessed number of days in the past 30 when health problems prevented respondents from conducting their usual daily activities. Regression analyses estimated associations of insomnia with days-out-of-role controlling comorbidity.

Results: Insomnia was significantly associated with days-out-of-role (.90 days/month) in a gross model. The association was reduced when controls were introduced for comorbidity (.42 days/month). This net association did not vary with number or type of comorbid conditions but was confined to respondents 35+ years of age. Insomnia was one of the most important conditions studied not only at the individual level, where it was associated with among the largest mean days-out-of-role, but also at the aggregate level, where it was associated with 13.6% of all days-out-of-role.

Conclusions: Insomnia has a strong net association with days-out-of-role that does not vary as a function of comorbidity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living*
  • Adolescent
  • Adult
  • Age Factors
  • Aged
  • Attitude to Health*
  • Comorbidity
  • Diagnostic and Statistical Manual of Mental Disorders
  • Disability Evaluation
  • Double-Blind Method
  • Female
  • Health Surveys
  • Humans
  • International Classification of Diseases
  • Male
  • Mental Disorders / epidemiology
  • Middle Aged
  • Prevalence
  • Sleep Initiation and Maintenance Disorders / epidemiology*
  • Sleep Initiation and Maintenance Disorders / psychology*
  • Surveys and Questionnaires
  • United States / epidemiology
  • Young Adult