Cognitive-behavioral and response-prevention treatments for bulimia nervosa.

This study was designed to assess the additive effects of major components of cognitive-behavioral treatment for bulimia nervosa. Seventy-seven female patients with bulimia nervosa were allocated at random to one of four conditions: wait-list control, self-monitoring of caloric intake and purging behaviors, cognitive-behavioral treatment, and cognitive-behavioral treatment combined with response prevention of vomiting. In the treatment conditions, participants were seen individually for fourteen 1-hr sessions over a 4-month period. All the treatment groups showed significant improvement, whereas the wait-list control group did not. Cognitive-behavioral treatment was, however, the most successful in reducing purging and in promoting positive psychological changes. Fifty-six percent of participants in this condition ceased binge eating and purging by the end of treatment, and the frequency of purging declined by 77.2% during the same period. Of the three treatment conditions, only cognitive-behavioral treatment was superior to the wait-list control. At the 6-month follow-up, 59% of the cognitive-behavioral group were abstinent, and purging had declined by 80%. Cognitive-behavioral treatment was significantly superior to the other treatment groups at this time. Thus, the addition of response prevention of vomiting did not enhance the efficacy of cognitive-behavioral treatment, and the evidence suggests that it may have had a deleterious effect.