New diagnostic criteria for insomnia and the association between insomnia, anxiety and depression.
Inger Sofie Olufsen, Marie E. Sørensen, Bjørn Bjorvatn
Studien er publisert i Tidsskrift for Den norske legeforening
BACKGROUND: The diagnostic criteria for insomnia in the Diagnostic Statistical Manual of Mental Disorders, version 5 (DSM-5), have been changed. The same changes are expected to be made in the International Classification of Diseases, version 11 (ICD-11). In this study, we examine the impact of the changes in the diagnostic criteria for insomnia on the association between insomnia, anxiety and depression.
MATERIAL AND METHOD: The study is based on a questionnaire survey with 68 questions that can be found on the website of the Norwegian Competence Centre for Sleep Disorders. The survey began in 2012, and our data were retrieved in 2016. The survey included validated questionnaires for insomnia, anxiety and depression: the Bergen Insomnia Scale and the Hospital Anxiety and Depression Scale (HADS).
RESULTS: A total of 48 932 participants met the DSM-IV diagnostic criteria for insomnia. Of these, 42 873 (87.6 %) also met the DSM-5 diagnostic criteria for insomnia, while the remaining 6059 (12.4 %) did not satisfy the new criteria. Of those who met the DSM-IV diagnostic criteria for insomnia, 46 704 also responded to the questions on anxiety and depression. The prevalence of possible anxiety (HADS-A ≥ 8) among those who met the new criteria was 25 708 (62.9 %), while the prevalence of possible depression (HADS-D ≥ 8) was 15 591 (38.1 %). Among the participants who did not satisfy the new criteria, the prevalence was significantly lower: possible anxiety 2791 (48.1 %) and possible depression 1763 (30.4 %) (both p < 0.001).
INTERPRETATION: The study indicates that the new diagnostic criteria for insomnia strengthened the association between insomnia, anxiety and depression. This may mean that with the new diagnostic criteria, more patients with insomnia will have comorbid mental disorders.