Are the Criterion B binge-eating symptoms interchangeable in understanding binge-eating severity? An item response theory analysis

Objective: The Criterion B binge-eating symptoms represent five symptoms associated with binge eating. Any three out of five symptoms can be used to meet Criterion B. However, Criterion B symptoms may not be interchangeable in terms of how binge-eating severity is associated with each symptom. Item response theory (IRT) can test how endorsing each symptom relates to the overall level (i.e., severity) of binge-eating measured by Criterion B. We used IRT to identify (a) how each Criterion B symptom corresponded with binge-eating severity in a transdiagnostic binge-eating sample and (b) how well each symptom differentiated individuals with differing levels of severity. Method: Participants (N = 219) were adults (80.8% female) with a current ED that included objective binge-eating episodes assessed via semi-structured interview. A two-parameter logistic IRT model evaluated how endorsement of each Criterion B symptom corresponded with the level of latent binge-eating severity. Results: “Eating large amounts when not hungry” and “eating alone” reflected the highest binge-eating severity. “Eating alone” was the best discriminator across different binge-eating severity levels, whereas “uncomfortably full” was the poorest discriminator across binge-eating severity levels. Discussion: Criterion B symptoms were not interchangeable in terms of what level of binge-eating severity corresponded with symptom endorsement. “Eating large amounts when not hungry” or “eating alone” may signify elevated binge-eating severity, whereas “uncomfortably full” and “feeling disgusted/depressed/guilty” were not necessarily indicative of elevated severity. Results suggested that Criterion B may need to be revised to eliminate symptoms that are redundant with other binge-eating diagnostic criteria.