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

Introduction: Concomitant anxiety and insomnia is a frequent problem encountered by mental health professionals. Primary objective: To assess the impact of cognitive-behavior therapy for insomnia (CBT-I) on associated anxiety. Method: Systematic search for clinical trials of CBT-I in Psyclnfo, Medline, and Proquest Dissertations and Theses. Results: Of 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. Conclusions: CBT-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. (C) 2011 Elsevier Ltd. All rights reserved.