Evaluating new severity dimensions in the DSM‐5 for bulimic syndromes using mixture modeling

Abstract

Proposed DSM-5 severity dimensions reveal ambiguity regarding the extent to which certain features define boundaries between similar diagnoses or represent underlying dimensions within a broader category of bulimic syndromes. The current study utilized a novel mixed modeling approach that can simultaneously model latent dimensions and latent categories to address this ambiguity. Data from structured clinical interviews in 528 adult participants were analyzed. A three-class solution with one severity dimension that was invariant across groups provided the best-fitting model. Both latent Classes 1 and 2 included bulimic syndromes but were distinguished by greater purging and weight phobia in latent Class 1. Latent Class 3 resembled a noneating disorder class. External validation analyses supported significant differences among empirically derived groups. Weight phobia contributes to categorical distinctiveness among bulimic syndromes whereas other features (purging, binge eating, and weight) may do so only in specific combinations. Uniform severity criteria may be appropriate across bulimic syndromes.