Acceptance and commitment therapy as a novel treatment for eating disorders: An initial test of efficacy and mediation

Eating disorders are among the most challenging disorders to treat, with even state-of-the-art cognitive behavioral treatments achieving only modest success rates. One possible reason for the high rate of treatment failures for eating disorders is that existing treatments fail to attend sufficiently to critical aspects of the disorder such as experiential avoidance, poor experiential awareness, and lack of motivation. These variables are explicit targets of acceptance and commitment therapy (ACT) and as such this approach may represent an ideal intervention for eating disorders. However, ACT has not been well investigated in this population. The current study sought to examine the efficacy of an ACT treatment group for eating disorders by examining whether the addition of ACT groups to treatment as usual (TAU) at a residential treatment facility for eating disorders will improve treatment outcomes. Results indicated that individuals in the ACT condition trended towards lower levels of eating pathology at post-treatment and showed significant reductions in bulimic symptoms and lower rates of inpatient treatment by follow-up. Some preliminary evidence suggests that Anorexia Spectrum patients may have done better in the ACT condition compared to Bulimia Spectrum patients. Other moderation analyses suggested that session attendance and higher levels of ACT consistent variables at baseline predicted a better response to ACT treatment. Although most mediation analyses were not significant, a small proportion suggested that willingness to experience distress was more highly associated with treatment outcome for the ACT condition. Overall, results suggest that ACT could be a viable treatment option for individuals with eating pathology and more study of ACT as an individual treatment is warranted.