Q & A: Does This Patient Have Bulimia Nervosa?

Q: I see a patient who is of normal weight, menstruates regularly, and purges, but really doesn’t binge eat. Does she have bulimia nervosa (BN)? (A.F., Atlanta)

A: The patient you’re describing isn’t that uncommon. Technically, she’d currently fall under the diagnosis of an eating disorder not otherwise specified (EDNOS), since she doesn’t meet criteria for having eating binges. However, some authorities are now delineating a syndrome referred to as “purging disorder,” i.e., women who are of normal weight, who don’t eat particularly large amounts before they purge, and who’ve never had BN. Your patient would seem to qualify for that group.

In studies comparing patients with purging disorder, traditional BN, and normal controls, those with purging disorder strongly resemble patients with BN in a number of respects. For example, they rate similarly for eating disorder severity, body image disturbance and dietary restraint. The differences are that women with BN have greater disinhibition around food and greater hunger compared to women with purging disorder (Int J Eat Disord 2005; 38: 191). For women who purge without binging, compulsive purging may become a habitual method these patients learn to use to reduce their anxiety.

Future studies will have to determine whether these groups differ in initial vulnerabilities and pathogenesis. For example, are women who develop BN more likely to tend to weigh more than those who simply develop purging disorder? Are those who develop purging disorder more likely to have earlier histories of rumination or regurgitation? Also needed are studies to examine similarities and differences with regard to course and outcome, particularly potential crossovers with a diagnosis of anorexia nervosa, and responses to various treatment modalities.

— J.Y.