Early response and 8-week treatment outcome in GAD

Our objective was to compare the predictive value of early response to treatment outcome in patients with generalized anxiety disorder (GAD) treated with benzodiazepines, serotonin receptor (5HT-1A) partial agonists, or placebo. Data from two double-blind GAD studies were combined. Subjects were evaluated with the Hamilton Anxiety Scale (HAM-A) and the Clinical Global Impression of Improvement (CGI-I) scale over 8 weeks. Categories of response at weeks 1 and 2 were defined by the HAM-A total score. Analyses of covariance and Kaplan-Meier survival analyses were the primary analyses used to assess 8-week end point treatment outcomes as a function of early improvement. HAM-A change from baseline to weeks I and 2 significantly predicted last observation carried forward (LOCF) response at week 8 for both medications and for placebo (P < .001). Early improvement was a strong predictor for treatment outcome irrespective of whether active medication or placebo was the treatment agent.