Prevalence and severity of eating disorders: A comparison of DSM-IV and DSM-5 among German adolescents.

Objective: Changes in the DSM-5 eating disorders criteria sought to increase the clarity of the diagnostic categories and to decrease the preponderance of nonspecified eating disorders. The first objective of this study was to analyze how these revisions affect threshold and EDNOS/OSFED eating disorder diagnoses in terms of prevalence, sex ratios, and diagnostic distribution in a student sample. Second, we aimed to compare the impairment levels of participants with a threshold, an EDNOS/OSFED and no diagnosis using both DSM-IV and DSM-5.

Method: A sample of 1654 7th and 8th grade students completed self-report questionnaires to determine diagnoses and impairment levels in the context of an eating disorder prevention program in nine German secondary schools. Height and weight were measured.

Results: The prevalence of threshold disorders increased from .48% (DSM-IV) to 1.15% (DSM-5). EDNOS disorders increased from 2.90 to 6.23% when using OSFED-categories. A higher proportion of girls was found throughout all the diagnostic categories, and the sex ratios remained stable. The effect sizes of DSM-5 group differences regarding impairment levels were equal to or larger than those of the DSM-IV comparisons, ranging from small to medium.

Discussion: We provide an in-depth overview of changes resulting from the revisions of DSM eating disorder criteria in a German adolescent sample. Despite the overall increase in prevalence estimates, the results suggest that the DSM-5 criteria differentiate participants with threshold disorders and OSFED from those no diagnosis as well as or even more distinctly than the DSM-IV criteria.