A Changing Dialogue in Treatment of Bulimia Nervosa?

During an ongoing clinical trial comparing group cognitive-behavioral therapy (CBT) with online CBT for patients with bulimia nervosa (BN), Dr. Cynthia M. Bulik and her colleagues began noticing that more individuals presenting for treatment were in the overweight or obese weight ranges (Am J Psychiatry. 2012; 169:1031). This observation coincided with a report from Spain indicating that obesity had increased threefold in patients with eating disorders characterized by binge eating (Eur Eat Disord Rev. 2012; 20:250). And, not only were patients seeking treatment for binge eating and purging, but they also expected treatment to lead to demonstrable weight loss.

What was happening? The authors surmised that in the context of the escalating obesity epidemic, the body mass index “weightscape” of patients with BN might be changing, with concurrent overweight or obesity now complicating the clinical picture and influencing patients’ expectations of treatment.

BMIs of patients with BN are generally in the normal or high-normal range, with lower BMIs associated with a history of AN. A patient’s BMI when he or she presents for treatment only tells a partial story, according to the authors because the clinical trajectory of BN often includes significant changes in weight. Actual or feared weight gain during treatment is a detriment to engagement in and acceptance of any interventions, both pharmacologic and psychological. And, as patients recover from BN, they may experience weight gain after they stop purging but continue binge eating. The authors encourage patients with BN to be mindful that their metabolism may take time to stabilize after binge eating and purging stop, and urge them not to take on extreme weight control behaviors in response to small changes in weight.

A growing conversation about weight

The authors also report that while supervising group therapy sessions and reviewing chat room transcripts, they noticed a marked difference in the therapeutic conversation about weight. They were surprised to find that therapy topics among normal-weight patients were not about striving for a societal ideal. Instead, normal-weight patients were discussing directives from their primary care physicians to lose weight or talking about their personal health concerns about type 2 diabetes, hypercholesterolemia, hypertension, and other medical complications of overweight and obesity. Since half of the authors’ patients were participating in online therapy, the authors did not always have visual cues to a patient’s weight. A check of the baseline demographic data showed that the mean BMI of the sample of patients using their website fell into the overweight (BMI= 25.2 kg/m²) or obese range. These overweight or obese patients were clearly entering treatment with two very clear treatment goalsabstinence from bulimic behaviors and weight loss. The current approach to BN, however, is not designed to promote weight loss. The authors considered the irony that in binge eating disorder (BED), where BMIs are often higher, cognitive behavior therapy (CBT), their standard treatment, could effectively produce abstinence from binge eating but was fairly ineffective for producing weight loss.

Matching patient expectations and therapy

The authors became concerned about a possible mismatch between the therapist’s and the patient’s treatment goals, which might contribute to dropout from treatment. They also determined that their intervention for BN would change, to consider all relevant health goals. If patients had weight-related medical comorbidities and gained weight during the course of CBT for BN, this might inadvertently exacerbate other health problems.

Thus, according to the authors, the conversation about weight in CBT for BN may have to vary, depending on the medical status of the individual patient, and it should carefully consider all the health parameters related to the patient’s current BMI. Two of the co-authors, Drs. Marsha Marcus and Michele Levine, suggest one approach to this problem. At the beginning of treatment for BED, they emphasize to patients that CBT is not associated with weight loss. In fact, traditionally, CBT for BED helps the patient accept a larger body size by promoting recognition that a larger body can be both attractive and healthy. Working toward acceptance of a larger body size is important for helping the patient avoid extreme dieting and unhealthy weight control practices that perpetuate disordered eating, but it also does not provide a license to ignore health risks associated with obesity.

In the absence of specific guidelines, Dr. Bulik and colleagues recommend that clinicians begin with a comprehensive evaluation of patients’ weight histories, including highest and lowest past adult BMI; childhood and adolescent weight and weight concerns; the frequency and duration of weight fluctuations; and deviations from both highest and lowest adult BMIs. Family weights and medical history will help determine both the likelihood that a patient will gain or lose weight with treatment and also obesity-related health risks.

Once this is established, the clinician and patient can work together to establish treatment goals. Pairing known CBT tools to reduce binge eating and purging with approaches to healthy lifestyle changes and appetite awareness, regular physical activity, and a focus on moderation all will help the BN patient address his or her dual concerns.

Discussion about weight regulation and desires for weight loss can also have some negative effects. For example, it can be a trigger for patients with a history of anorexia nervosa and may exacerbate the urge to restrict food. Or, for overweight patients in group therapy with low-weight patients, such a discussion may result in negative body comparisons and lead to early dropout from treatment.

BN may represent a natural evolution of the eating disorder in individuals who are also overweight or obese. The authors urge clinicians to be alert to this possible trend in individuals with BN, and to adapt interventions appropriately.