A randomized trial of two group-delivered transdiagnostic eating disorder treatments: Dissonance-based treatment versus interpersonal psychotherapy.

Objective: Test whether a group-delivered dissonance-based transdiagnostic eating disorder treatment, Body Project Treatment (BPT), produces greater reductions in eating disorder symptoms and higher abstinence from eating disorder behaviors and remittance from eating disorder diagnoses than group-delivered transdiagnostic interpersonal psychotherapy (IPT).

Method: Women with a range of eating disorders (N = 73) were randomized to 8-week group-implemented BPT or IPT and completed surveys and masked diagnostic interviews at pretest, posttest, and 6-month follow-up.

Results: Participants randomized to BPT versus IPT showed significantly greater reductions in eating disorder symptoms (d = -.75), pursuit of the thin ideal (d = -.87), anxiety symptoms (d = -.76), and social impairment (d = -.59) through 6-month follow-up. By end of treatment, participants randomized to the BPT versus IPT did not significantly differ on abstinence from binge eating and purging (49% vs. 40%, respectively) or remittance from eating disorder diagnoses (54% vs. 40%, respectively). Participants randomized to BPT versus IPT did not differ significantly in average session attendance (5.8 vs. 6.9, respectively) or average homework assignments completed (4.6 vs. 5.6, respectively). The within-condition reductions in eating disorder symptoms for BPT did not significantly differ when implemented in person versus via synchronous video telepsychiatry (d = -1.39 vs. -1.09, respectively), though these effects should be considered preliminary because of the small cell sizes.

Conclusions: The evidence that BPT produces greater reductions in eating disorder symptoms, pursuit of the thin ideal, anxiety symptoms, and social impairment than IPT is encouraging because it provides some assurance that the effects are present equating for the effects of expectancies, demand characteristics, and nonspecific factors. (PsycInfo Database Record (c) 2023 APA, all rights reserved).