What is the key distinguishing feature between anorexia nervosa and bulimia nervosa in the provided material?

• A. BMI
• B. Age at onset
• C. Frequency of binge eating
• D. Laxative use

Answer: (A)

Body weight status, reflected by BMI, is what distinguishes anorexia nervosa from bulimia nervosa. In anorexia nervosa, restrictive eating leads to significantly low body weight, with BMI well below the normal range. In bulimia nervosa, binge eating occurs with compensatory behaviors, but overall weight tends to be normal or overweight because those behaviors offset the binges. That weight pattern is the defining contrast clinicians use.

Age at onset can vary and overlap between the disorders, so it’s not a reliable differentiator. Binge eating frequency is central to bulimia, but the key is whether weight is significantly low or not. Laxative use can occur in various patterns and isn’t the primary distinguishing feature. Keep in mind that a binge-purge subtype can appear in anorexia nervosa, but the general diagnostic distinction centers on weight status.