Transdiagnostic CBT May Be Effective for Most Outpatients

About 80% of outpatients with eating disorders have eating disorders not otherwise specified (EDNOS). Results from a novel study in Great Britain have demonstrated the efficacy of a manual-based treatment for these patients. In addition, the treatment, which used two forms of cognitive behavioral therapy (CBT), was useful or helpful for most outpatients with an eating disorder (Am J Psychiatry 2009; 166:311).

Dr. Christopher G. Fairburn and colleagues compared two forms of “enhanced” CBT treatment in outpatients with eating disorders at two treatment centers. One treatment focused solely on eating disorder features (CBT-Ef), and the other was a more complex form of CBT that addressed mood intolerance, clinical perfectionism, and interpersonal difficulties (CBT-Eb). The 154 subjects had a DSM-IV eating disorder but were not markedly underweight (body mass index over 17.5 kg/m2) and were enrolled in a two-site randomized controlled trial involving 20 weeks of treatment and follow-up at 20, 40, and 60 weeks. The control condition was an 8-week waiting list period before treatment. The outcomes were measured by independent assessors who were blinded to the treatment condition.

Patients were assessed with the Eating Disorder Examination (EDE) and its self-report version (EDE-Q). The assessors were blinded to the patients’ treatment condition and were not involved with treatment. General psychiatric features were measured with the Brief Symptom Inventory and the Structured Clinical Interview for DSM-IV was used at baseline to identify the presence of coexisting axis I psychiatric disorders.

A substantial response among all patients

There was a substantial response to treatment across all measures, and no significant differences emerged between the two treatments. Patients in the waiting-list control condition group showed little change in severity of symptoms, whereas those in the two treatment conditions showed substantial and equivalent changes, which they maintained during the follow-up period. Most importantly, treatment outcome did not depend on the original eating disorder diagnosis.

Patients with marked mood intolerance, clinical perfectionism, low self-esteem, or interpersonal difficulties seemed to respond better to the more complex treatment, and the opposite pattern was evident among the remaining patients.

More than 40% of the potentially eligible patients did not take part because of the length of the study (28 weeks) and their desire not to participate in research. Few of the participants had binge eating disorder.

Four findings

First, the authors found that it was feasible to treat a broad range of patients using one of the two forms of enhanced CBT. Secondly, the symptoms among those in the control group were unchanged at the end of the study period. While absence of change among patients with bulimia nervosa (BN) is not surprising, the authors point out that this is the first time that such data have been reported for patients with EDNOS. The third finding was that the patients responded well to both treatments, and the DSM-IV diagnosis was not a moderator of outcome.

At the end of 20 weeks (the first follow-up period), more than half of each group of patients with BN and EDNOS, 53.7% and 53.0%, respectively, had levels of eating disorder features less than 1 standard deviation above the community mean. At the 60-week follow-up, the comparable figures were 61.4% and 45.7%, respectively. The fourth finding concerned the relative effects of the two forms of CBT. In the full sample, they weren’t different in effectiveness. However, a more in-depth analysis showed that the CBT-eb form of treatment was more effective for patients with substantial additional psychopathology.