Aims: The present study was conducted to investigate the effectiveness of DBT-PE combined treatment protocol, dialectical behavior therapy, and prolonged exposure therapy in reducing self-injury behaviors of veterans with PTSD. Materials & Methods: This experimental study was conducted with a pre-test/post-test design with a control group and a follow-up. The statistical population of the research was made up of all veterans with PTSD who were referred to Isar Psychiatric Hospital in Ardabil, Iran, in 2022. The research sample consisted of 80 veterans with PTSD, who were selected from the statistical population as a purposeful sampling, considering the acceptance of veterans to participate in the research in the first place and having the entry criteria. To collect data, the Inventory of Statements about Self-injury was used. The first experimental group received DBT (10 sessions of 90 minutes), the second experimental group received PE (10 sessions of 90 minutes), and the third experimental group received DBT-PE (16 sessions of 90 to 120 minutes). Findings: All three intervention methods were effective in reducing self-injury behaviors of veterans with PTSD (p<0.01); However, the effect of combined treatment was greater than the other two interventions (p<0.05). Conclusion: The combined treatment method has a greater effect in reducing self-injury behaviors in veterans with PTSD compared to prolonged exposure therapy and dialectical behavior therapy. Also, prolonged exposure therapy has a greater effect than dialectical behavior therapy.
