Predicting Outcome in Bulimia Nervosa

A clinical marker may help clinicians determine which patients with bulimia nervosa being treated with cognitive behavioral therapy (CBT) will have a better prognosis than others. Recently researchers found that patients whose purging had been reduced by 70% one-third of the way through treatment with CBT had a much better outcome than patients who did not significantly change their pattern of purging.

W. Stewart Agras, MD, and colleagues at 3 treatment centers evaluated the pretreatment, course of treatment, and outcome data for 194 women who met the DSM-III-R criteria for bulimia nervosa (Am J Psychiatry 2000; 157:1302). The women were treated with 18 sessions of manual-based CBT. The differences between the dropouts and non-dropouts and between recovered and non-recovered bulimics were first examined descriptively, and then signal detection analyses were used to determine clinically significant cutoff points predicting attrition and abstinence from purging.

Characteristics of dropouts

Dr. Agras and his co-workers found that women who dropped out of therapy had more severe bulimic cognitions and greater impulsivity. In addition, those who were treatment failures had poor social adjustment and a lower body mass index, which may have been a sign of dietary restriction. Early progress in therapy was the best predictor of outcome. Those with a poor treatment outcome did not decrease purging by at least 70% by the sixth treatment session. The early marker enables clinicians to try alternative therapies for bulimics who do not respond to CBT.