Copyright @ 2008 American Academy of Child and Adolescent Psychiatry. Unauthorized reproduction of this article is prohibited. Predictors and Moderators of Outcome in Family-Based Treatment for Adolescent Bulimia Nervosa DANIEL LE GRANGE, PH.D., ROSS D. CROSBY, PH.D., AND JAMES LOCK, M.D., PH.D. ABSTRACT Objective: To explore the predictors and moderators of treatment outcome for adolescents with bulimia nervosa (BN) who participated in family-based treatment or individual supportive psychotherapy. Method: Data derived from a randomized controlled trial (n = 80) of family-based treatment of BN and supportive psychotherapy were used to explore possible predictors and moderators of treatment outcome. Results: Participants with less severe Eating Disorder Examination eating concerns at baseline were more likely to have remitted (abstained from binge eating and purging) after treatment (odds ratio [OR] 0.47; p < .01) and follow-up (OR 0.53; p < .01), regardless of the treatment that they received. Participants with lower baseline depression scores were more likely to have partial remission (no longer meeting study entry criteria) after treatment (OR 0.93; p < .01), whereas those with fewer binge-eating/purging episodes at baseline were more likely to have partial remission at follow-up (OR 0.98; p < .05). In terms of moderators, participants with less severe eating disorder psychopathology (Eating Disorder Examination global score), receiving FBT-BN, were more likely to meet criteria for partial remission at follow-up (OR 0.44; p < .05). Conclusions: Lower eating concerns are the best predictor of remission for adolescents with BN, and family-based treatment of BN may be most effective in those cases with low levels of eating disorder psychopathology. J. Am. Acad. Child Adolesc. Psychiatry, 2008;47(4):464Y470. Key Words: bulimia nervosa, family-based treatment, predictors, moderators, outcome. Clinical trial registration informationVFamily Therapy for Adolescent Bulimia NervosaVURL: http://clinicaltrials.gov. Unique identifier: NCT00518843. A range of efficacious treatments for adults with bulimia nervosa (BN) has been developed and tested. 1Y5 In stark contrast, efficacious treatments for adolescents with BN have not received much inquiry, despite the fact that these behaviors typically have their onset during adolescence. 6 Only two randomized controlled trials for this patient population have been published to date, one from a group in London, 7 and the other from our own group in Chicago. 8 Both of these trials compared a form of family treatment with a comparison therapy. Given that treatment studies for adolescent BN are in their infancy, findings from these controlled studies should be considered as preliminary, or a first step in our understanding of efficacious treatments for this patient population. Kraemer and colleagues 9 argue that more can be ascertained from randomized controlled trials than the evaluation of the efficacy of treatments. For instance, additional inquiries can identify for whom treatment may work (moderators) or the mechanisms through which a treatment may achieve its aims (mediators). Such knowledge serves a dual purpose in that it informs clinical practice and helps channel future studies. 9 Few previous treatment studies of eating disorders have conducted predictor/moderator or mediator analyses. 10Y14 Among these, and most relevant to the current investigation, are findings from the adolescent anorexia nervosa (AN) studies Accepted August 17, 2007. Dr. Le Grange is with the Department of Psychiatry, University of Chicago; Dr. Crosby is with the Neuropsychiatric Research Institute and the University of North Dakota School of Medicine and Health Sciences; and Dr. Lock is with the Department of Psychiatry and Behavioral Sciences, Stanford University. This research was supported by grant K23 MH001923 from the NIMH (Dr. Le Grange). Correspondence to Dr. Daniel Le Grange, Department of Psychiatry, University of Chicago, 5841 S. Maryland Avenue, MC3077, Chicago, IL 60637; e-mail: legrange@uchicago.edu. 0890-8567/08/4704-0464Ó2008 by the American Academy of Child and Adolescent Psychiatry. DOI: 10.1097/CHI.0b013e3181640816 464 WWW.JAACAP.COM J. AM. ACAD. CHILD ADOLESC. PSYCHIATRY, 47:4, APRIL 2008