Determining the effectiveness of cognitive behavioral therapy interventions based on the transdiagnostic approach in the treatment of common mental health problems: Presenting an experience from the Islamic Republic of Iran.

Introduction: There is growing support to develop transdiagnostic approaches that provide new insights into mental health problems and cut across the existing traditional diagnostic boundaries all over the world. The present study was conducted to test the transdiagnostic cognitive behavioral therapy (TCBT) approach in treating patients with common mental health problems and evaluate its effectiveness compared to the current treatment settings of the healthcare system.

Methods: A randomized controlled trial was conducted in Semnan Province, north of Iran. The study took pace in urban health centers. A sample of 520 Iranian adults, tested as positive on the Kessler Psychological Distress Scale, were enrolled. Participants who received a score above the cut-off point in any of the three mental health disorders (depression, anxiety, or obsessive compulsive disorder [OCD]) based on the locally validated study instrument were randomly allocated to the study. The intervention group received TCBT during eight sessions provided by trained general health service providers without previous mental health training; the standby control group received Mental Health Services as Usual (MHSU). The post-test interviews were conducted using the study instrument after the completion of both group treatments.

Results: A total of 459 individuals (87.8% female) ultimately entered the study. The withdrawal rate was 24% (53 participants in the TCBT and 56 in the MHSU). Reduction in depression, anxiety, and OCD symptoms was significant within each group and when comparing TCBT and MHSU (mean difference).

Conclusion: This trial recommends that the transdiagnostic CBT approach can be effective in improving common mental health problems and functions among individuals by trained general healthcare providers in the primary healthcare system. The results can be more useful in decision making when defining the process of providing mental healthcare in the National Primary Healthcare System.