Reciprocal Dynamics of Therapeutic Alliance and Depressive Symptoms in Inpatient Cognitive Behavioural Analysis System of Psychotherapy: The Role of Attachment Insecurity.

BACKGROUND: Persistent depressive disorder (PDD) is marked by interpersonal dysfunction, presenting significant challenges for effective treatment. The Cognitive Behavioural Analysis System of Psychotherapy (CBASP) is specifically designed for PDD, offering a structured framework to foster a meaningful therapeutic relationship. However, its effectiveness in patients with attachment insecurities-commonly observed in PDD-remains unclear. This study examined the bidirectional relationship between the therapeutic working alliance and depressive symptoms, alongside the moderating role of attachment anxiety and attachment avoidance, in patients undergoing inpatient CBASP. METHODS: A total of 164 patients completed a 10-week inpatient CBASP programme. Depressive symptoms and the therapeutic working alliance were assessed weekly via self-report measures, while attachment anxiety and attachment avoidance were evaluated before and after treatment. Linear mixed-effects models were employed to analyse symptom and alliance trajectories, their reciprocal influences and the moderating effects of attachment insecurity. RESULTS: Over the course of treatment, depressive symptoms significantly decreased, while therapeutic alliance scores significantly increased. In addition, attachment anxiety decreased significantly. Attachment anxiety and attachment avoidance did not significantly moderate changes in depressive symptoms or therapeutic working alliance over time. Increases in the working alliance predicted subsequent reductions in depressive symptoms, and improvements in symptoms predicted subsequent strengthening of the working alliance. Attachment anxiety and attachment avoidance did not moderate these reciprocal associations. CONCLUSION: Findings demonstrate a robust bidirectional relationship between working alliance and depressive symptomatology, independent of attachment insecurity. A brief CBASP intervention effectively reduces symptoms and strengthens the therapeutic alliance, highlighting its clinical utility in treating PDD.