Reductions in transdiagnostic factors as the potential mechanisms of change in treatment outcomes in the Unified Protocol: a randomized clinical trial.

Transdiagnostic approaches emphasize on the share underlying features of emotional disorders. In their view, these transdiagnostic factors play an important role in the etiology, maintenance, and treatment of emotional disorders. This study aimed to investigate the transdiagnostic factors as the potential mechanisms of change in the Unified Protocol (UP) for the transdiagnostic treatment of emotional disorders outcomes. The present study is a randomized clinical trial. Twenty-six individuals were selected based on the Beck anxiety inventory and Beck depression inventory and randomly assigned into two groups of control and treatment (n=13). The treatment group received 20 one-hour individual UP sessions. Beck Depression Inventory, Beck Anxiety Inventory, Difficulty in emotion regulation scale, Intolerance of Uncertainty scale and Acceptance and Action questionnaire were carried out in all three phases. UP enhances the difficulty in emotion regulation (large effect size, SEsg=1.81), intolerance of uncertainty (SEsg=1.91), and experiential avoidance (SEsg=1.78). In addition, the results of linear regression show the association between changes in anxiety and depression with changes in transdiagnostic factors. The difficulty in emotion regulation, intolerance of uncertainty and experiential avoidance can be considered as the potential mechanism of change in improving UP outcomes.