A Comparison of Bulimia Nervosa and Its OSFED Variant on Trait and Behavioural Indicators of Reward Constructs

Abstract

ABSTRACT Introduction Although individuals with bulimia nervosa (BN) demonstrate elevated reward sensitivity and reward valuation‐effort (RV‐e) compared to controls, whether BN differs from its other specified feeding or eating disorder variant (OSFED‐BN), remains unclear. Further, whether differences best reflect categorical distinctions or correlations with symptom severity is unknown. This study examined whether trait and behavioural reward indicators differentiate BN, OSFED‐BN, and controls, predict diagnostic status, and correlate with bulimic symptom severity. Methods Participants were 349 women (153 BN, 118 OSFED‐BN, 78 controls). Group comparisons, multinomial logistic regression, and correlational analyses were conducted on the Sensitivity to Punishment/Sensitivity to Reward‐Reward subscale (SPSRQ‐Reward), Behavioural Activation System‐Drive (BAS‐Drive) scale, and progressive ratio tasks assessing RV‐e for food and game rewards. Results BN and OSFED‐BN demonstrated higher SPSRQ‐Reward scores than controls but did not differ from each other. OSFED‐BN, but not BN, showed higher food and game RV‐e compared to controls. SPSRQ‐Reward predicted higher odds of BN or OSFED‐BN versus controls, whereas BAS‐Drive predicted lower odds. SPSRQ‐Reward was positively associated with bulimic symptom frequencies. Food RV‐e was inversely associated with purging frequency. Discussion Findings supported the role of reward‐related processes in contributing to both dimensional and categorical differences between BN, OSFED‐BN, and controls.