A meta-analytic review of the efficacy of pharmacological treatment in generalized anxiety disorder was conducted. The main substance classes were compared: benzodiazepines and azapirones. The impact of methodological variables was investigated such as sample size and use of a placebo run-in. After a comprehensive literature search to May 2002 (via databases, hand search, secondary sources, internet, contact of researchers, and pharmaceutical companies), the results of 48 studies were integrated. Weighted Hedges g was computed and a random-effects analysis was done. Effect sizes were computed for anxiety, depression, and clinical significance. Sensitivity analyses were conducted. Pharmacotherapy was superior to placebo in all symptom categories. Azapirones and benzodiazepines were equally effective. Compliance (as measured by dropout rate) was higher for benzodiazepines. Only sample size was significantly associated with effect size. Pharmacotherapy, especially benzodiazepines and azapirones, is effective in the short-term treatment of patients with generalized anxiety disorder. There was no superiority of 1 drug class in reducing symptomatology.
*Department of Psychology, University of Jena, Germany; †Central Institute of Mental Health, Mannheim, Germany and ‡Department of Psychology, University of Tübingen, Germany.
Received October 21, 2003; accepted after revision July 13, 2004.
The study reports results from the dissertation of the first author, completed under the supervision of Peter Noack and Martin Hautzinger. Results were partly presented at the 33rd Congress of the European Association of Behavioural and Cognitive Therapy (EABCT), September 10 to 13, Prague, Czech Republic.
Address correspondence and reprint requests to Kristin Mitte, PhD, Department of Psychology, University of Jena, Am Steiger 3, Hs. 1, 07745 Jena, Germany. E-mail: firstname.lastname@example.org.