Change in Patients' Interpersonal Impacts as a Mediator of the Alliance-Outcome Association in Treatment for Chronic Depression

Objective: Theories posit that chronically depressed individuals have hostile and submissive interpersonal styles that undermine their interpersonal effectiveness and contribute to the cause and maintenance of their depression. Recent findings support this theory and demonstrate that chronically depressed patients' interpersonal impacts on their therapist become more adaptive (i.e., less hostile and submissive, and more friendly and assertive) during a targeted chronic depression treatment: cognitive-behavioral analysis system of psychotherapy (CBASP). In this study, the authors examined whether such changes in interpersonal impacts (as rated by clinicians' experiences of interacting with their patients) mediated the association between early patient-rated alliance quality and final session depression. Method: Data derived from a large trial for chronic depression that compared the efficacy of CBASP, nefazodone, and their combination. The current subsample (N = 220) included patients in the CBASP and combined conditions who completed at least 1 depression assessment and the alliance measure, and whose therapists completed at least 1 interpersonal impacts assessment. Mediation models were fit using a bootstrapping procedure for assessing indirect effects. Results: As hypothesized, results supported a mediating effect; higher early alliance predicted decreases in patient hostile-submissiveness during therapy, which in turn related to lower final session depression (indirect effect B = -.02, 95% confidence interval: -.07, -.001). This indirect effect accounted for 13% of the total effect of alliance on depression. There was no moderating effect of treatment condition on the indirect effect. Conclusions: Results further support CBASP change theory and suggest a candidate mechanism of the alliance's effect on outcome.