Relation of patient and therapist interpersonal impact messages to outcome in interpersonal therapy for depression.

Interpersonal depression theories posit that excessive submissiveness in social interactions perpetuates negative mood. Correspondingly, many psychotherapies postulate that improvement can be facilitated by patient−therapist interactions. However, few studies have tested in-session patient and therapist behaviors that should, in theory, associate with depression reduction. Addressing this gap, the present study examined such associations in interpersonal psychotherapy (IPT). We hypothesized that decreases in patients’ submissive interpersonal impacts on their therapist would be associated with greater depression reduction, as would increases in therapists’ friendly submissive impacts on their patient; theoretically, such therapist behavior would pull for patients to complement it with adaptive assertiveness, thereby disrupting their submissive tendencies. Data derived from an open trial of 16 IPT sessions for adults with major depression. Patients (N = 119) and therapists (N = 39) rated the others’ interpersonal impacts at Sessions 3 and 16 via the Impact Message Inventory. Patients rated their depression on the Beck Depression Inventory—Second Edition after each session. As predicted, multilevel modeling revealed that decreases in patients’ submissive impacts were associated with greater concurrent depression reduction (p = .03) and lower posttreatment depression level (p = .03). Also, although therapists did not differ in their change in friendly submissive impacts, thus precluding a test of the influence of such change on outcome, a greater average level of therapist friendly submissiveness related to lower posttreatment depression (p = .008). Results support interpersonal depression theories and the therapeutic benefit of specific patient and therapist change processes in IPT. (PsycINFO Database Record (c) 2018 APA, all rights reserved)