Therapeutic Alliance, Self-efficacy, and Agency as Mechanisms of Change in Blended Care and Routine Psychotherapy

Blended Care (BC) has emerged as a promising approach to address the growing demand for accessible mental health treatment. While BC is effective for various mental disorders, little is known about the mechanisms through which BC leads to change and how they compare to traditional psychotherapy. This study investigates whether therapeutic alliance, general and mental health self-efficacy, and therapeutic agency function as mechanisms of change in BC and face-to-face psychotherapy (PT). We conducted a secondary analysis of a randomized controlled trial (N = 1,159 patients) comparing BC to PT in routine outpatient care in Germany. Mechanism and outcome variables (mental distress, satisfaction with life) were assessed at four time points over six months. Random-intercept cross-lagged panel models (RI-CLPM) were used to differentiate stable between-person associations from temporal within-person effects. Both self-efficacy constructs and therapeutic alliance were associated with better outcomes in both treatments. Agency was associated with higher life satisfaction but not symptom reduction. Temporal effects indicated that increases in mental health self-efficacy and therapeutic alliance predicted improved outcomes at the following time point. General self-efficacy and agency showed inconsistent effects, with counterintuitive findings in the BC group where higher self-efficacy and agency predicted more distress or less life satisfaction. Outcomes also predicted changes in mechanisms, indicating reciprocal dynamics. Differences between BC and PT were only significant for general self-efficacy. Our findings suggest that therapeutic change is dynamic and reciprocal. The unexpected association of higher self-efficacy and increased distress in the BC group needs replication.