Objective: Interpersonal theories posit that chronically depressed individuals have hostile and submissive styles in their social interactions, which may undermine their interpersonal effectiveness and maintain their depression. Recent findings support this theory and also show that patients' interpersonal impact messages, as perceived by their psychotherapists, change in theoretically predicted ways following cognitive-behavioral analysis system of psychotherapy (CBASP) alone or with medication. This study extended these previous findings by examining whether such changes were associated with their depression change and response status.
Method: Data derived from a large clinical trial for chronic depression compared the efficacy of CBASP, nefazodone, and their combination. To assess patients' impact messages, CBASP clinicians completed the Impact Message Inventory (IMI; Kiesler & Schmidt, 1993) following an early and late session. Our subsample (N = 259) consisted of patients in the CBASP and combined conditions who had depression severity data for at least 1 post-randomization visit and whose clinicians completed at least 1 IMI rating. We used hierarchical linear modeling (HLM) to calculate IMI change scores and to model depression change. We used HLM and logistic regression to test our predictor questions.
Results: As hypothesized, decreases in patients' hostile-submissive impact messages were significantly associated with depression reduction (γ = 0.27, 95% CI [0.11, 0.43], p < .01) and favorable treatment response (B = -0.05, 95% CI [-0.09, -0.01], p = .03), regardless of treatment condition.
Conclusions: The findings support CBASP theory, suggesting that interpersonal change is related to depression reduction among chronically depressed patients.