784 Am j Psychiatry 148:6, June 1991 Severity of Depression and Response to Cognitive Behavior Therapy

Objective: The authors studied the relationship between clinical severity ofdepression and response to cognitive behavior therapy. Method: Fifty-nine outpatients with major depres-sion with endogenous features, according to Research Diagnostic Criteria, were stratified into more severe (score of2O or more on the Hamilton Rating Scale for Depression; N=38) or less severe (Hamilton score of 1 9 or less; N=21) subgroups. Patients were treated with a 1 6-week, 20-session cognitive behavior therapy protocol. Outcome was assessed with the Hamilton scale, the Global Adjustment Scale, and the Beck Depression Inventory. Results: The more severe group was significantly more symptomatic across the 1 6-week protocol and had a significantly lower response rate on the Beck inventory (50 % versus 81 %). However, the groups did not significantly differ at end point on any of the three measures, and they showed comparable rates of symptomatic improvement (i.e., percent change in scores and interactions between severity classification and time). Conclusions: These results partially replicate the National Institute of Mental Health ‘s Treatment of Depression Collaborative Research Program ‘s findings of poorer response to cognitive behavior therapy in patients with Hamilton scale scores of 20 or more. However, both groups experienced robust an