Excessive Avoidance Behaviors in Anorexia Nervosa: the Role of Reward

Anorexia Nervosa (AN) is a life-threatening mental disease with a disappointing treatment outcome. Fear of weight gain and diet restrictions are considered the core symptoms of AN. Although from a diagnostic perspective AN is conceptualized as an eating-related disorder connected to an extremely low Body Mass Index (BMI) and body image distortion, AN might represent a specific phenotype of anxiety disorders characterized by tenacious avoidance behaviors, especially the restrictive subtype. To date, avoidance in AN is often investigated as a general personality trait (e.g. harm avoidance) but poorly examined in its behavioral form (which is life-threatening, such as food-avoidance). Hence, the investigators will perform a systematic investigation of excessive avoidance behaviors within a laboratory setting. Within a learning perspective, the investigators will investigate excessive avoidance in a group of 30 AN patients and 30 healthy volunteers. To achieve this, a well-validated avoidance paradigm will be used. Most critically, the investigators will examine whether patients with a diagnosis of anorexia nervosa show persistent avoidance behaviors compared to a control group. Additionally, the investigators will examine if, in the anorexia group, higher subjective relief to successful omissions of negative events during avoidance learning predicts persistent (excessive) avoidance behaviors after fear extinction.