Reduced sympathetic activity and dysfunctional metacognition in patients with Anorexia Nervosa: A preliminary study

The present study explored the association between some psychological symptoms related to worry, metacognition, and autonomic activity, in a group of 13 patients with Anorexia Nervosa (AN) as compared to 13 healthy controls (HCs). Specifically, trait and state anxiety, obsessive-compulsive symptoms and metacognitive beliefs were assessed through self-report questionnaires. Heart rate (HR) and skin conductance (SC), as representative measures of autonomic activation, were recorded at rest. Patients with AN reported significantly higher anxiety, obsessive-compulsive symptoms and maladaptive metacognitions than HCs. Further, patients showed significantly lower skin conductance level (SCL) and HR than HCs, pointing to an overall autonomic hypo-activation, which was uncorrelated with psychological symptoms. A significant correlation was observed between HR, but not SCL, and body mass index (BMI) in patients, suggesting that autonomic hypo-activation could only partially be ascribed to the reduced body weight, as measured through BMI. Remarkably, a significant negative correlation was found between patients' SCL and a metacognitive dimension (i.e., the negative beliefs concerning the consequences of not controlling thoughts), which may have critical implications for AN treatment.