Evaluation of the DSM-5 Severity Specifier for Bulimia Nervosa in Treatment-Seeking Youth

A new severity specifier for bulimia nervosa (BN), based on the frequency of inappropriate weight com-pensatory behaviours (e.g., laxative misuse, self-induced vomiting, fasting, diuretic misuse, and excessive exer-cise), has been added to the most recent (fifth) edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) as a means of addressing variability and heteroge-neity in the severity of the disorder. While existing research provides support for the DSM-5 severity specifier for BN in adult patients, evidence for its validity and clinical util-ity in youth is currently lacking. To address this gap, data from 272 treatment-seeking adolescents with DSM-5 BN (94.2% female, Mage = 15.3years, SD 1.7) were analysed to examine whether these patients, sub-grouped based on the DSM-5 severity definitions, would show meaningful dif-ferences in a broad range of clinical variables and demo-graphic and physical characteristics. Analyses revealed that participants categorized with mild, moderate, severe, and extreme severity of BN significantly differed from each other in 15 variables regarding eating disorder pathologi-cal features and putative maintenance factors (i.e., core low self-esteem, perfectionism, social appearance anxiety, body surveillance, and mood intolerance), health-related quality of life and comorbid psychiatric (i.e., affective and anxiety) disorders (large effect sizes). Between-group differences in demographics, body mass index, or age-of-BN onset were not observed. Collectively, our findings provide support for the utility of the frequency of inappropriate weight com-pensatory behaviours as a severity indicator for BN and suggest that age-at-onset of BN is probably more disorder- than severity-dependent. Implications for future research are outlined