Consistency of reward responses in neutral and anxious states in adolescent females with anorexia nervosa.

BACKGROUND: Anorexia nervosa (AN) is a difficult-to-treat psychiatric disorder that typically onsets in adolescence. AN is marked by atypical reward responsiveness and elevated anxiety. However, the neural dynamics of reward responsivity, and how this is impacted by being in an anxious state, are unknown in AN. To test this, we conducted a novel fMRI task consisting of a monetary reward following anxiety provocation or a neutral condition. METHODS: Forty-seven adolescent participants (25 females with partially or fully weight restored AN, post treatment and 22 mildly anxious controls) were presented with personalized anxiety-provoking or neutral words before receiving a reward. Mildly anxious controls were included to enable dimensional analysis of anxiety severity and to assess whether anxiety effects were specific to AN. To measure trial-by-trial consistency of multivariate patterns associated with reward, and the effects of anxiety on reward, neural responses across reward circuit and cognitive reward control regions were analyzed using representational similarity analysis. RESULTS: As hypothesized, AN participants showed lower representational similarity than controls during neutral-word rewarded trials, indicating more variable reactivity to rewarding outcomes. Contrary to predictions, there were no significant between-group differences for the effects of anxiety-words on reward representational similarity, and representational similarity did not predict longitudinal symptom change over six months. CONCLUSIONS: The results demonstrate more variable responses to reward receipt in AN compared with controls, but no significant effects of anxiety states on the consistency of reward responses. These results provide insight into the dynamics of reward processing in AN, which has potential implications for planning and guiding reward-focused interventions.