Pupil psychosensory reflex in response to own and standardised silhouettes in patients with anorexia nervosa.

Objective: This study aimed to assess the physiological response of patients with anorexia nervosa (AN) to different types of silhouettes using pupillometry. Methods: We measured the pupil psychosensory reflex (PSR) of 42 patients with AN and 35 healthy controls in response to standardised body silhouettes and to pictures of their own silhouettes digitally modified to represent different body mass indices (BMI). Perceptual distortion and body dissatisfaction were assessed using Anamorphic Micro Software©. Twenty‐three of the recruited patients were tested up to four times during an inpatient treatment programme to assess the impact of weight gain. Results: PSR correlated with the subjective rating of emotional arousal in controls but not in patients. Own silhouettes and standardised silhouettes triggered a different pupil response both in patients with AN and in controls. With pictures of their own silhouettes, pupil response to underweight stimuli differed from pupil response to normal weight or overweight stimuli in both groups. Weight gain was associated with an increase in PSR, an improvement of ideal BMI and a decrease of body dissatisfaction, but no change in perceptual distortion. Conclusion: Our findings support the idea that pupillometry could be a useful tool to assess the physiological state of patients with AN. Key points: Standardised body silhouettes and subjects' own silhouettes trigger different pupil responses in both patients with anorexia nervosa (AN) and healthy controls.Pupil response to underweight silhouettes differs from pupil response to normal weight and overweight silhouettes.Weight gain is associated with an evolution of pupil reactivity in patients with AN. [ABSTRACT FROM AUTHOR]