Avoidance habit learning in adolescents and young women with anorexia nervosa: an fMRI study

Anorexia nervosa (AN), often with an onset in adolescence, is a complex eating disorder characterized by distorted body image, fear of weight gain, and extreme food restriction, leading to severe underweight. Excessive goal pursuit and avoidance behaviors have been proposed as key factors in AN, which over time may become over-trained into habits. This study investigated the behavioral and neural correlates of habit learning in AN with an experiment consisting of three consecutive phases: (1) training goal-directed behavior, (2) avoidance learning, and (3) a habit test. Forty-five acutely underweight adolescent female patients with AN and 45 age-matched healthy control participants underwent an fMRI scan. No behavioral group differences were evident either during learning of avoidance habits or when testing habit strength. Importantly, however, the AN group showed both generally superior task performance and increased involvement of the frontoparietal brain regions during habit learning. Collectively, our findings provide novel evidence suggesting that excessive goal pursuit may predominate in young AN in an avoidance learning context. Future research should examine if this tendency develops into habit learning over time and investigate the speed and strength of avoidance habit formation in adults with a longer history of AN to further elucidate the intricate dynamic between goal-directed and habitual processes in the disorder.