Validity and reliability of the Brief Insomnia Questionnaire in the general population in Hong Kong.

Objectives: The Brief Insomnia Questionnaire (BIQ) was first validated in the U.S. for insomnia disorders according to the Diagnostic and Statistical Manual, Fourth Edition, Text Revision (DSM-IV-TR), International Classification of Diseases, Tenth Edition (ICD-10) and research diagnostic criteria/International Classification of Sleep Disorders, Second Edition (RDC/ICSD-2). We aimed to determine the validity and reliability of a Hong Kong Chinese version of the BIQ to derive the DSM-5 in addition to other insomnia diagnoses in a general population sample.

Methods: Probability subsamples of population-based epidemiological survey respondents (n=2011) completed test-retest (n=120) and clinical reappraisal (n=176) interviews.

Results: Short-term test-retest reliability was moderate for most BIQ items (Pearson r>0.40), except for the number of nights with problems staying asleep, amount of time awake, duration of sleep problems and sleep onset latency. The areas under the receiver operating characteristic curve for the DSM-IV-TR, DSM-5, ICD-10 and RDC/ICSD-2 insomnia disorder ranged from 0.76 to 0.86, indicating high individual-level concordance between BIQ and clinical-interview diagnoses. The use of super-normal control and BIQ symptom-level data further improves the diagnostic concordance. Prevalence estimates based on the BIQ dichotomous classification were comparable with estimates based on clinical interviews for the DSM-5, RDC/ICSD-2 and any of the DSM-IV-TR, ICD-10 and RDC/ICSD-2 insomnia disorders.

Conclusion: The Hong Kong Chinese version of the BIQ generates accurate prevalence estimates for insomnia disorders in the general population. Modification of the BIQ scoring algorithms and use of trained interviewers may further improve its diagnostic performance.