CBASP model can be effective for treating persistent depressive disorder

Persistent depressive disorder (PDD) is very common and debilitating, but only few therapeutic options exist that target this form of depression.

Guidelines recommend treating PDD with the Cognitive Behavioral Analysis System of Psychotherapy (CBASP). The effectiveness of CBASP has been demonstrated in numerous randomized controlled trials but very few of these trials have specifically examined mediators of treatment effect that are specific to the CBASP model.

This model states that a novel relational experience in the therapeutic alliance is necessary for interpersonal change to occur and that this interpersonal change in turn leads to improvement of depression.

This study analyzes data of a multicenter RCT comparing CBASP to Supportive Psychotherapy (SP). In CBASP, the therapeutic relationship is explicitly targeted using techniques that are collectively labeled disciplined personal involvement.

Results showed that a significant part of the association between treatment and outcome is mediated through the sequential indirect effect of improvement in alliance and reduction in the interpersonal problems.

Based on these findings, the superior efficacy of CBASP compared to SP might be explained by a greater effect of CBASP on the therapeutic relationship that in turn contributes to improved interpersonal functioning.

Even though it remains unclear to what extent the CBASP techniques of disciplined personal involvement contributed to the mediation effect, a previous study suggest that situational analysis mediates the association between the therapeutic alliance and outcome.

During situational analysis, the focus is on the patient's interpersonal behavior occurring outside the session. While the ability of patients to perform situational analysis did contribute to the outcome, it did not mediate the alliance-outcome association. This strengthens the argument that personal involvement techniques explain the mediation effect.

This study contributes to the understanding of the well-established association between alliance and outcome and suggests that these results might extend to other psychotherapies, at least those specifically targeting interpersonal functioning.

These therapies seem to exert their effect at least in part through techniques aimed at fostering corrective relational experiences which facilitate interpersonal change.