Diminished Adaptation, Satisfaction, and Neural Responses to Advantageous Social Signals in Anorexia Nervosa and Bulimia Nervosa.

BACKGROUND: Development and recurrence of two eating disorders (EDs), anorexia nervosa and bulimia nervosa, are frequently associated with environmental stressors. Neurobehavioral responses to social learning signals were evaluated in both.

METHODS: Adult women with anorexia nervosa (n = 25), bulimia nervosa (n = 30), or comparison (n = 38) played a neuroeconomic game in which the norm shifted, generating social learning signals (norm prediction errors [NPEs]) during a functional magnetic resonance imaging scan. A Bayesian logistic regression model examined how the probability of offer acceptance depended on cohort, block, and NPEs. Rejection rates, emotion ratings, and neural responses to NPEs were compared across groups.

RESULTS: Relative to comparison, both ED cohorts showed less adaptation (p = .028, ηp 2 = .060) and advantageous signals (positive NPEs) led to higher rejection rates (p = .014, ηp 2 = .077) and less positive emotions (p = .004, ηp 2 = .111). Advantageous signals increased neural activations in OFC for comparison women but not for those with anorexia nervosa (p = .018; d = 0.655) or bulimia nervosa (p = .043; d = 0.527). More severe eating disorder symptoms were associated with decreased activation of dorsomedial prefrontal cortex for advantageous signals.

CONCLUSIONS: Diminished neural processing of advantageous social signals and impaired norm adaptation were observed in both anorexia nervosa and bulimia nervosa, while no differences were found for disadvantageous social signals. Development of neurocognitive interventions to increase responsivity to advantageous social signals could augment current treatments, potentially leading to improved clinical outcomes for eating disorders.