Reliability and validity of the brief insomnia questionnaire in the America insomnia survey.

Study Objectives: to evaluate the reliability and validity of the Brief Insomnia Questionnaire (BIQ), a fully structured questionnaire developed to diagnose insomnia according to hierarchy-free Diagnostic and Statistical Manual, Fourth Edition, Text Revision (DSM-IV-TR), International Classification of Diseases-10 (ICD-10), and research diagnostic criteria/International Classification of Sleep Disorders-2 (RDC/ICSD-2) general criteria without organic exclusions in the America Insomnia Survey (AIS).

Design: probability subsamples of AIS respondents, oversampling BIQ positives, completed short-term test-retest interviews (n = 59) or clinical reappraisal interviews (n = 203) to assess BIQ reliability and validity.

Setting: the AIS is a large (n = 10,094) epidemiologic survey of the prevalence and correlates of insomnia.

Participants: adult subscribers to a national managed healthcare plan.

Intervention: None

Measurements And Results: BIQ test-retest correlations were 0.47-0.94 for nature of the sleep problems (initiation, maintenance, nonrestorative sleep [NRS]), 0.72-0.95 for problem frequency, 0.66-0.88 for daytime impairment/distress, and 0.62 for duration of sleep. Good individual-level concordance was found between BIQ diagnoses and diagnoses based on expert interviews for meeting hierarchy-free inclusion criteria for diagnoses in any of the diagnostic systems, with area under the receiver operating characteristic curve (AUC, a measure of classification accuracy insensitive to disorder prevalence) of 0.86 for dichotomous classifications. The AUC increased to 0.94 when symptom-level data were added to generate continuous predicted-probability of diagnosis measures. The AUC was lower for dichotomous classifications based on RDC/ICSD-2 (0.68) and ICD-10 (0.70) than for DSM-IV-TR (0.83) criteria but increased consistently when symptom-level data were added to generate continuous predicted-probability measures of RDC/ICSD-2, ICD-10, and DSM-IV-TR diagnoses (0.92-0.95).

Conclusions: these results show that the BIQ generates accurate estimates of the prevalence and correlates of hierarchy-free insomnia in the America Insomnia Survey.