Suspect an eating disorder? Suggest CBT

ILLUSTRATIVE CASE

A 23-year-old patient with a body mass index (BMI) of 18 tells you she’s fat and she’s afraid of gaining weight. Further questioning reveals that your patient binges on cookies and potato chips about once a week, then compensates for overeating by taking laxatives or exercising excessively—a practice she’s been following since she started college several years ago. The eating disorder she describes does not meet the criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) for bulimia or anorexia nervosa, although it has elements of both. Rather, it fits the diagnostic criteria for eating disorder NOS. You’re aware that CBT is the first-line behavioral treatment for bulimia, and wonder whether it would be helpful for your patient.

Eating disorders often go undetected and untreated in primary care practices,³ as many patients don’t volunteer information about their weight or behaviors related to food, and physicians often fail to ask. Overall, as few as 10% of those with eating disorders receive any form of treatment.¹

Would you recognize this loosely defined disorder?

In the United States, the lifetime prevalence of eating disorders is 0.6% for anorexia nervosa (0.3% for men and 0.9% for women), 1.0% for bulimia (0.5% for men and 1.5% for women), and 2.8% for binge-eating disorder (2.0% for men, 3.5% for women).⁴ Eating disorder NOS, which encompasses subthreshold cases of anorexia or bulimia, patients with elements of both anorexia and bulimia, and patients with binge-eating disorder, accounts for 50% to 80% of eating disorder diagnoses in outpatient settings. Yet there have been few studies of the treatment of these patients.^2,5,6

A review of DSM-IV criteria

The diagnostic criteria for anorexia nervosa include a refusal to maintain a weight of at least 85% of normal body weight (or having a BMI ≤17.5), intense fear of gaining weight, disturbance in the way one’s body shape is experienced, and amenorrhea in females who are post-menarche.

Criteria for bulimia include recurrent episodes of binge eating (consuming a large amount of food with a sense of lack of control over eating) and recurrent inappropriate compensatory behaviors to prevent weight gain (self-induced vomiting, excessive exercise, fasting, laxatives, diuretics, or enemas) at least twice weekly for 3 months; and self-evaluation that is unduly influenced by body shape and weight.⁷ Most patients with eating disorder NOS have clinical features of both anorexia and bulimia.⁶

APA guidelines are silent on NOS

CBT has consistently proven to be the most useful behavioral treatment for patients with bulimia.¹ Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine—the only medication with Food and Drug Administration approval for the treatment of an eating disorder⁸ —are about as effective as CBT, and the combination of CBT and an SSRI is superior to either treatment alone.⁹ CBT has also been found to be somewhat effective in treating binge-eating disorder.¹⁰

Anorexia nervosa, the most deadly eating disorder (the mortality rate is 6.6%¹¹ ) and the most difficult to treat, is the exception. Several studies have assessed CBT for treating anorexia, but it has not been found to be very effective.^10,12,13

The 2006 American Psychiatric Association practice guidelines for the treatment of patients with eating disorders feature recommendations for anorexia, bulimia, and binge-eating disorder, but do not address eating disorder NOS.¹⁰ The National Institute for Clinical Excellence (NICE) in the United Kingdom issued guidelines for the treatment of eating disorders in 2004. In response to the lack of evidence for treating eating disorder NOS, NICE recommended basing treatment on the form of eating disorder that most closely resembles the patient’s presentation.¹⁴ Fairburn et al addressed the lack of evidence for treatment of eating disorder NOS with the study summarized here.