Abstract
Introduction: Dialectical behavior therapy is one of the third wave treatments whose effectiveness in a range of mental disorders has been tested. The purpose of this study was to evaluate the effectiveness of dialectical behavior therapy on anxiety and rumination in depressed patients.
Materials & Methods: The research method was quasi-experimental with pretest-posttest design with two groups (test and control). The statistical population consisted of Naja staff referred to the consulting unit of Mashhad Samen Alaemeh Hospital in Mashhad in 1397, using a convenience sampling method of 27 depressed individuals with a cut-off score of 14 on the Beck Depression Inventory (BDI-II) and a score of equal to or above 16 in The Beck Anxiety Inventory (BAI) was selected and randomly divided into two groups: dialectical behavior therapy of 13 subjects and control of 15 subjects. Beck Anxiety Questionnaire (1993) and Rumination Response Scale (1991) were administered to both groups before treatment. Then, dialectical behavioral group therapy was administered to the experimental group based on the therapeutic guidelines in eight sessions for four weeks and the control group received no treatment. Finally, the two groups completed the research scales. Follow-up evaluation was also performed three months after treatment.
Results: Repeated measures analysis of variance was used to analyze the data. The findings show that dialectical behavior therapy emphasized on reducing anxiety and rumination, and the improvement observed in the experimental group was maintained at 3-month follow-up.                                             
Conclusion: Thus, the findings of the present study demonstrate the effectiveness of dialectical behavior therapy in improving pathological rumination and reducing anxiety in depressed patients.