Theoretical accounts posit that chronically depressed individuals are perceived as hostile and/or submissive, which compromises their ability to satisfy their interpersonal needs. The current study assessed the interpersonal tenets of McCullough's (2000) chronic depression theory and examined change in interpersonal functioning following McCullough's treatment for chronic depression (viz., Cognitive-Behavioral Analysis System of Psychotherapy; CBASP). Data derive from a randomized 12-week clinical trial that compared the efficacy of CBASP, nefazodone, and their combination for chronic depression. To assess patients' interpersonal impacts, CBASP therapists completed the Impact Message Inventory (IMI) following an early and a late session. IMI data were compared to normative and clinical comparison samples to assess depression-related interpersonal profiles and clinically significant change in interpersonal functioning. As predicted, chronically depressed patients were initially perceived as more submissive and hostile than the comparison groups. Patients' interpersonal impacts on their therapists changed in adaptive, theoretically predicted ways by the end of CBASP treatment, either with or without medication. Individual-level clinical significance data were less robust. The findings generally substantiate McCullough's interpersonal theory and provide preliminary evidence of change in interpersonal impacts following treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved).