Multidimensional Assessment of Orthorexia Nervosa: A Case-Control Study Comparing Eating Behavior, Adherence to the Mediterranean Diet, Body Mass Index, Psychological Symptoms, and Autonomic Arousal

<b>Background:</b> The research on orthorexia nervosa (ON) has thoroughly outlined the connection between it and various mental disorders, including obsessive-compulsive disorders and eating disorders, in addition to stress. However, research has not considered psychophysical stress and other measures of psychophysical health, such as adherence to the Mediterranean diet. <b>Methods:</b> This cross-sectional and case-control research involved 63 students from the University of Parma, aged between 18 and 49 years. The ORTO-15 questionnaire was utilized to categorize the entire sample into two groups: one without orthorexia (score > 35) and another with orthorexia (score < 35). All subjects were assessed with the Psychophysiological Stress Profile (PSP) and completed the Eating Disorder Inventory-3 (EDI-3) and the Symptom Checklist-90-Revised (SCL-90-R). In addition, they were interviewed using the PREDIMED questionnaire to assess adherence to the Mediterranean Diet, and their body mass index (BMI) was calculated. <b>Results:</b> Subjects with orthorexia represented 38.10% of the total sample and reported a higher BMI than controls, although the PREDIMED score did not show a difference in adherence to the Mediterranean diet. The EDI-3 highlighted emotional dysregulation and hypercontrol in students with orthorexia, and a dissociation between subjective and objective measures of stress emerged. Particularly, the psychophysiological parameters of skin conductance, heart rate, and heart rate variability showed greater reactivity to stressful stimuli, but no difference was noted in psychological symptoms. <b>Conclusions:</b> These findings confirmed the presence of alterations in eating behavior in people with orthorexia as well as a higher BMI. It was hypothesized that hypercontrol might favor the perception of psychological well-being at a subjective level, although inadequate management of stress emerged at an objective psychophysiological level. Further studies are needed to highlight the causality between ON, hypercontrol, diet, and psychophysical stress, given that students with orthorexia present a dysregulation of emotions associated with greater autonomic arousal.