ABSTRACT
Acceptance and commitment therapy [ACT] is a new method of psychotherapy for major depressive disorder [MDD]. The aim of this experimental study is evaluating the effectiveness of acceptance and commitment therapy and cognitive therapy. In this randomized clinical trial, 19 depressive out-patients were randomly divided into 2 groups [acceptance and commitment therapy and cognitive therapy]. Twelve therapeutic sessions administered in consulting center of Tehran University twice a week. All the subjects were tested by Beck Depression Inventory [BDI-II]] and the Ruminative Response Scale [RRS] before and after the treatments. Data were analyzed by multivariate analysis of covariance [MANCOVA]. The results show no significant differences between the two groups in terms of the variables of depression and rumination. Overall, the results suggest that ACT is an effective treatment, the effectiveness of which appears equivalent to that of CT