Meta-Analysis of Treatments for Depression, Panic, and GAD
Citation: Westen, D., & Morrison, K. (2001). A multidimensional meta-analysis of treatments for depression, panic, and generalized anxiety disorder: an empirical examination of the status of empirically supported therapies. Journal of Consulting and Clinical Psychology, 69(6), 875-899.
This meta-analysis draws a distinction between initial response and sustained efficacy and attempts to determine the sustained efficacy of evidence-based treatments. This is particularly useful in their examination of GAD, for which a sizable percentage of clients experience significant improvements even before seeing a therapist for the first time. The analysis included five controlled studies of GAD which generally excluded comorbid conditions and had high completion rates.
The analysis found a clinically meaningful effect size for a majority of clients meeting criteria for GAD, although the majority of these clients retained “mild but clinically significant” symptoms after treatment. Data to determine the sustained efficacy of the examined EBTs, however, are unavailable. The authors point out the serious questions that this lack of data raises about the status of current evidence-based treatments for GAD. Whereas EBTs for panic disorder show promising results, those for depression demonstrate sustained efficacy of only 25-30% over 12-24 months. Until long term follow-up data is available for GAD EBTs, their recommendation as empirically supported interventions remains dubious.