The impact of social rejection on implicit food biases in patients with Restrictive Anorexia Nervosa: a mobile app study.

Anorexia nervosa is a severe psychiatric disorder with a significant global and individual impact, characterized by numerous comorbid psychiatric conditions and elevated mortality rates. This complex condition is associated with pathological neurocognitive patterns, leading to the pathognomonic features of distorted body perception, food avoidance, and restriction, resulting in severe weight loss, malnutrition, and subsequent physical, social, and psychological consequences. Anorexia nervosa development is rooted in altered psychological and behavioural responses to food and body-related stimuli and abnormal functioning of the reward system. Our study aims to investigate behavioural food biases in patients with AN and their possible alterations in response to an induced state of social rejection, hypothesizing that this negative social context might exacerbate or modify these pre-existing biases. The research was carried out using a mobile app. Via this app, the participants were exposed to three videos of a person addressing them with negative comments, then they carried out tasks in which they had to push their phone away or pull it towards themselves while the app displayed different visual cues (high-calorie foods, low-calorie foods, or neutral objects). We then analyzed the reaction times of the patient and the control groups to the visual cues as recorded by the phone accelerometer, and we compared the results obtained in a neutral state with those obtained in the social rejection state.