Methods This research was administered in three stages. First, a psycho-cognitive remediation treatment manual was developed based on the most reliable existing treatments: Cognitive Behavior Therapy (CBT) and Cognitive Remediation Therapy (CRT). In the second stage, the content validity of the manual was evaluated by 8 experts. Finally, the effectiveness of the developed treatment was evaluated by the quasi-experimental method with an active control group, pretest-posttest follow-up design. 28 adults aged 24-45 years who had been diagnosed with MDD were purposefully selected and assigned to one of the two experimental or control groups. The experimental group participated in 12 two-hour weekly sessions and the control group played video games at home. The Beck Depression Inventory-Second Edition (BDI-II) and the THINC-it tools as neuropsychological tests were used for gathering data. Only 25 patients remained in the study at week 12. To statistically analyze the data, One-way analysis of covariance was used (SPSS 26). Results Data analysis showed that depression and anhedonia were significantly lower at the post-test compared to the pre-test, according to the BDI-II and SHAPS scores. All objective and subjective cognitive functions were significantly improved. Follow-up scores remained significantly constant in the tests that had improved in the post-test which indicates the stability of therapeutic effects in the three-month follow-up. Conclusion This is the first study to evaluate two validated combined therapies in adults with MDD, as far as the authors are aware. It was evaluated based on feasibility, acceptability, and effectiveness. It is suggested that clinicians use these combined treatments in the field of clinical practice. Although this treatment manual had a good effect, some of its limitations must be addressed in future research.
