Orthorexia nervosa versus anorexia nervosa: Comparison of diagnostic and behavioral features in at-risk young adults.

Orthorexia nervosa (ON) has garnered increasing attention as a potential diagnostic entity, yet its nosological status remains unresolved. Given overlapping features between ON and anorexia nervosa (AN)/atypical AN, this study examined the extent to which consensus-based ON diagnostic criteria and distinguishing features of AN/atypical AN were endorsed by college students at risk for one, both, or neither syndrome. Participants (N = 916; 72.5% cisgender women; 73.9% Non-Latino) completed an online survey assessing ON symptoms, AN/atypical AN risk, and related clinical and behavioral features. The four groups were compared across syndrome features. Approximately 25% of the sample was at risk for AN/atypical AN, ON, or both syndromes. Individuals at risk for ON endorsed fewer body-related concerns compared to those at risk for AN/atypical AN, yet did not differ on dietary restriction, health anxiety, wellbeing, gender, or body mass index. Dietary patterns likewise largely overlapped across at-risk ON and AN/atypical AN groups, with effect sizes generally among the smallest observed. Findings indicate that ON may represent a non-fat-phobic or denial-based presentation of AN/atypical AN rather than a distinct syndrome, suggesting the utility of conceptualizing restrictive eating disorders along a spectrum of presentation and severity.