Cognitive Behavioral Treatment of Bulimia Nervosa

G. Terence Wilson, Ph.D.

Rutgers University

Reprinted from:
Wilson, G.T. (1997). Cognitive behavioral treatment of bulimia nervosa. The Clinical Psychologist, 50(2), 10-12.

I. Description of Treatment

Treatment is based on a model that emphasizes the critical role of both cognitive and behavioral factors in the maintenance of the disorder. Of primary importance is the value that attaches to an idealized body weight and shape. This leads women to restrict their food intake in rigid and unrealistic ways, a process that leaves them physiologically and psychologically susceptible to periodic loss of control over eating, namely binge eating. Purging and other extreme forms of weight control are attempts to compensate for the effects of binge eating. Purging helps maintain binge eating by reducing the patient's anxiety about potential weight gain and disrupting learned satiety that regulates food intake. In turn, binge eating and purging cause distress and lower self-esteem, thereby reciprocally fostering the conditions that will inevitably lead to more dietary restraint and binge eating. It follows from this cognitive model of the maintenance of bulimia nervosa that treatment must address more than the presenting behaviors of binge eating and purging. In addition, dietary restraint must be replaced with more normal eating patterns, and dysfunctional thoughts and feelings about the personal significance of body weight and shape must be altered. The cognitive model also suggests that treatment may need to address negative self-evaluation, perfectionism and dichotomous thinking, and perhaps also the ability to tolerate negative affect.

The commonly used form of cognitive-behavioral therapy (CBT) for binge eating and bulimia nervosa derives directly from Fairburn's first formulation of this approach in Oxford in a treatment manual in the early 1980's. A more recent, expanded version of this manual was published in 1993 (Fairburn, Marcus, & Wilson, 1993). Although there are differences in the ways in which cognitive-behavioral treatment has been implemented across different clinical and research settings, at the core, all are derived from the Oxford approach. It is the current Oxford manual that sets the standard for outpatient treatment of bulimia nervosa and is increasingly being adopted in major clinical research centers (Wilson, Fairburn, & Agras, in press).

II. Summary of Studies Supporting the Treatment's Efficacy

CBT for bulimia nervosa has been rigorously evaluated in over 20 controlled trials. Three main findings can be identified:

CBT has broadly beneficial effects on all aspects of the psychopathology of bulimia nervosa.
Frequencies of binge eating and purging are markedly reduced, dietary restraint is decreased, and the intensity of the concerns about shape and weight are attenuated if not normalized. Associated with these changes is a decrease in the level of general psychiatric symptoms and an improvement in self-esteem and social functioning. In Craighead and Agras's (1991) summary of 10 controlled trials they reported a mean reduction in the frequency of purging of 79% with 57% of patients being abstinent. Wilson and Fairburn (in press) pooled comparable data from nine additional controlled trials and obtained figures of 84% and 48% respectively for purging and 79% and 62% for binge eating.

CBT-induced improvement appears to be well-maintained.
CBT has durable effects. Available evidence suggests that therapeutic changes are well-maintained over the six to 12 months following treatment. The longest follow-up of CBT (mean length of follow-up = 5.8 years) found that roughly two-thirds of patients had no eating disorder, the great majority of whom were functioning well (Fairburn et al., 1995). This is an impressive outcome given the brevity of the treatment provided (19 sessions over 18 weeks), the chronicity of the eating disorder at presentation (the mean duration was almost seven years), and the care and rigor with which the follow-up assessments were conducted.

CBT has been found to be equal or superior to all the treatments with which it has been compared.
Aside from CBT, the most intensively researched treatment for bulimia nervosa is antidepressant medication, which has been shown consistently to be significantly more effective than pill placebo. Consequently, antidepressant medication provides a stringent standard of comparison for the effects of CBT. Studies that have directly evaluated the relative and combined effectiveness of CBT and antidepressant drug treatment have, as a whole, shown that CBT is superior to medication alone. Combining CBT with medication is significantly more effective than medication alone. Combining the two has produced few benefits over CBT alone on the reduction of the core features of bulimia nervosa. Also favoring CBT are the findings that it seems more acceptable to patients, and may result in fewer drop-outs. In contrast to the data on CBT, there is virtually no evidence of the long-term effect of pharmacological treatment.

CBT has proved to be more effective than several other psychological treatments, including supportive psychotherapy, supportive-expressive psychotherapy, stress management therapy, and a form of behavior therapy that did not address cognitive features of bulimia nervosa. The chief exception is focal interpersonal psychotherapy (IPT). A major comparative outcome study found that at the end of treatment IPT was less effective than CBT, but during follow-up the difference between the two treatments disappeared due to continuing improvement among the patients who received IPT (Fairburn et al., 1995).

At present, no other treatment, pharmacological or psychological, equals the efficacy of CBT. Nevertheless, it is also clear that no more than roughly 50% of patients cease binge eating and purging. Of the remainder, some show partial improvement, whereas a small number derive no benefit at all. Current CBT for bulimia nervosa has significant limitations. Attention must now be focused on devising treatment strategies for those patients for whom CBT is ineffective or insufficiently helpful.

III. References

Background Research

Agras, W.S., Schneider, J.A., Arnow, B., Raeburn, S.D., & Telch, C.F. (1989). Cognitive-behavioral and response-prevention treatments for bulimia nervosa. Journal of Consulting and Clinical Psychology, 57, 215-221.

Agras, W.S., Rossiter, E.M., Arnow, B., Telch, C.F., Raeburn, S.D., Bruce, B., & Koran, L. (1994). One-year follow up of psychosocial and pharmacologic treatments for bulimia nervosa. Journal of Clinical Psychiatry, 55, 179-183.

Craighead, L.W., & Agras, W.S. (1991). Mechanisms of action in cognitive-behavioral and pharmacological interventions for obesity and bulimia nervosa. Journal of Consulting and Clinical Psychology, 59, 115-125.

Fairburn, C.G., Norman, P.A., Welch, S.L., O'Connor, M.E., Doll, H.A., & Peveler, R.C. (1995). A prospective study of outcome in bulimia nervosa and the long-term effects of three psychological treatments. Archives of General Psychiatry, 52, 304-312.

Wilson, G.T., & Fairburn, C.G, (in press). Treatment of eating disorders. In P. E. Nathan & J. M. Gorman (Eds.) A guide to treatments that work. New York: Oxford University Press.

Clinical Applications

Fairburn, C.G., Marcus, M.D. & Wilson, G.T. (1993). Cognitive behaviour therapy for binge eating and bulimia nervosa: A comprehensive treatment manual. In C.G. Fairburn & G.T. Wilson (Eds.). Binge eating: Nature, assessment, and treatment (pp. 361-404). New York: Guilford Press.

Fairburn, C.G. & Wilson, G.T. (in press). Eating disorders. In K. Hawton, P. Salkovskis, J. Kirk, & D. Clark (Eds.) Cognitive behaviour therapy for psychiatric problems: A practical guide (2nd ed.). New York: Oxford University Press.

Garner. D.M., & Bemis. K.M. (1985). Cognitive therapy for anorexia nervosa. In D.M. Garner & P.E. Garfinkel (Eds.). Handbook of psychotherapy for anorexia nervosa and bulimia (pp. 107-146). New York: Guilford Press.

Wilson, G.T., Fairburn, C.G. & Agras, W.S. (in press). Cognitive-behavioral therapy for bulimia nervosa. In D.M. Garner & P.E. Garfinkel (Eds). Handbook of treatment for eating disorders. New York: Guilford Press.

IV. Resources for Training

Clinicians are advised to contact one of several leading clinical research centers or training programs featuring CBT for eating disorders. The following are some examples: Department of Psychiatry, Stanford University School of Medicine (Dr. Agras); Eating Disorders Clinic, New York State Psychiatric Institute, Columbia University (Kathy Pike); Psychology Department, University of Vermont (James Rosen and Harold Leitenberg); Psychology Department, California State University at San Diego (Denise Wilfley); Department of Psychology, University of Hawaii (Kelly Vitousek); Eating Disorders Clinic, Rutgers University (Terry Wilson).

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