Meta-analytic review of the impact of cognitive-behavior therapy for insomnia on concomitant anxiety

IntroductionConcomitant anxiety and insomnia is a frequent problem encountered by mental health professionals.Primary objectiveTo assess the impact of cognitive-behavior therapy for insomnia (CBT-I) on associated anxiety.MethodSystematic search for clinical trials of CBT-I in PsycInfo, Medline, and Proquest Dissertations and Theses.ResultsOf the 216 CBT-I trials reviewed, 72 (33.3%) reported data on anxiety. The combined effect size (ES) of CBT-I on anxiety was 0.406 [95% CI 0.318–0.493], indicating a small to moderate effect of CBT-I on concomitant anxiety. Anxiety and anxiety-related constructs were measured with 31 different questionnaires or questionnaire subscales, the majority of which were used only once in the sample of studies.ConclusionsCBT-I has only a moderate impact on anxiety in individuals who present insomnia with or without a comorbid anxiety disorder. A careful evaluation of residual anxiety should be conducted subsequent to CBT-I. Further research should focus on standardizing the assessment of anxiety in insomnia research.

Research highlights
► The combined ES of CBT-I on anxiety and anxiety-related constructs was moderate.
► The impact of CBT-I did not vary according to the presence of comorbidity.
► The inclusion of anxiety management strategies did not increase the impact of CBT-I.
► There is a lack of consensus regarding the assessment of anxiety in CBT-I.