A meta-analysis of CBT for pathological worry among clients with GAD.

Previous meta-analyses assessing the effectiveness of Cognitive Behavioural Therapy (CBT) for Generalized Anxiety Disorder (GAD) used general measures of anxiety to assess symptom severity and improvement (e.g., Hamilton Anxiety Ratings Scale or a composite measure of anxiety). While informative, these studies do not provide sufficient evidence as to whether CBT significantly reduces the cardinal symptom of GAD: pathological worry. The current meta-analysis employed stringent inclusion criteria to evaluate relevant outcome studies, including the use of the Penn State Worry Questionnaire as the main outcome variable. Results showed a large overall effect size (ES) that was moderated by age and modality of treatment. Specifically, the largest gains were found for younger adults and for individual treatment. Analyses also revealed overall maintenance of gains at 6- and 12-month follow-up. Clinical implications of different treatment packages are discussed, as well as potential explanations for the differential effectiveness of CBT.