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

Abstract

Objective 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. Method Data from structured clinical interviews in 528 adult participants were analyzed. Results A 3-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 non-eating disorder class. External validation analyses supported significant differences among empirically derived groups. Discussion 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.

The dimensional nature of eating pathology: Evidence from a direct comparison of categorical, dimensional, and hybrid models.

“…In particular, our results differ from Keel et al (2013) who also used the DCS approach and found evidence in favor of hybrid models. Our analyses of the “case-control” sample suggest that discrepant findings may due to the nature of the samples used.…”

“…Finally, similar to Keel et al (2013), we compared the fit of categorical, dimensional, and hybrid models to identify the best-fitting model for the nature of eating pathology. We also compared these same models in a “case-control” subset of our sample who endorsed substantial eating pathology versus no/little eating pathology.…”

The validity of DSM‐5 severity specifiers for anorexia nervosa, bulimia nervosa, and binge‐eating disorder

“…For instance, limited data exist regarding predictive validity of severity specifiers, and extant evidence has been inconclusive (Mustelin et al, 2016; Smink, van Hoeken, Oldehinkel, & Hoek, 2014). It is yet unclear whether the frequency of a single symptom or weight status alone are sufficient indices by which to characterize ED severity, as severity dimensions based on cognitive, affective, social, and biological domains may also yield clinically useful information (Grilo et al, 2008; Keel, Crosby, Hildebrandt, Haedt-Matt, & Gravener, 2013). It may be worth considering a multifaceted approach to characterize illness severity, and notably, the DSM-5 does not preclude the importance of other factors in determining severity (American Psychiatric Association, 2013; pp.…”

A review of purging disorder through meta-analysis.

“…Notably, a recent factor mixture analysis of bulimic syndromes indicated a single latent severity dimension in combination with three distinct classes, but did not support clear distinctions between BN, PD, and AN-bp. Rather, the majority of PD cases were subsumed with BN and AN-bp cases in a class characterized by purging, weight phobia, and a higher level of comorbidity (Keel et al, 2013). Taken together with the present results, PD may exist along a dimension of severity within bulimic spectrum disorders characterized by loss of control eating and purging behavior.…”

“…However, comparing PD with other EDs on indicators of concurrent and predictive validity may provide empirical evidence to inform future classification systems 2 (Kendell, 1989). Moreover, there is evidence to suggest that EDs are more accurately categorized based upon both qualitative differences and the degree of underlying severity (Keel, Crosby, Hildebrandt, Haedt-Matt, & Gravener, 2013). …”