Understanding the reward system functioning in anorexia nervosa: crucial role of physical activity

Hyperactivity is a potential neurobiological marker and a core psychopathological trait in anorexia nervosa (AN). We investigated the processing of hyperactivity-related information in fifteen AN patients, 15 athletes and 15 non-athletes to examine if they represent disorder-related reward information using eye tracking. We assessed the extent of individually performed physical activity, mood, trait reward sensitivity and serum leptin levels. Results revealed a pronounced bias in overall attentional engagement toward stimuli associated with physical activity in patients and athletes as compared to non-athletes. In patients, relevant correlations were found: trait reward sensitivity and attentional orienting were strongly correlated and amount of physical activity correlated with attentional orienting and engagement. Compared to non-athletes, patients and athletes rated exercise stimuli as more pleasant. Findings suggest that exercise-related stimuli are perceived as rewarding by AN patients. Positive motivational valence of physical activity might contribute to disorder development and maintenance.