Investigating the relationship between Orthorexia nervosa and autistic traits in a University population

Background: Orthorexia nervosa (ON) is an emerging condition featuring restrictive eating behaviours on the basis of subjective beliefs about food healthiness. Many authors have stressed the similarities between ON and Anorexia nervosa (AN) in both cognitive and behavioural patterns. Despite that, while the link between AN and female autism presentations is well-known in the literature, no study has yet investigated the relationship between ON and autism spectrum. This work aims to investigate the relationship between ON and autistic traits in a University population. Methods: An e-mail invitation was sent to all the students and employers of University of Pisa. Subjects were asked to fulfill the ORTO-15 and the Adult Autism Subthreshold Spectrum (AdAS Spectrum) questionnaires. Results: A total of 2426 subjects joined the survey: 623 subjects (26.3%) reported a score associated with significant orthorexic symptoms according to ORTO-15 (ON group), while 1789 subjects (73.7%) did not report ON symptomatology and were considered as healthy controls (HC). The ON group scored significantly higher on almost all AdAS Spectrum domains. Moreover, being female and scoring higher on AdAS Spectrum were statistically predictive factors for the presence of ON symptomatology. Among AdAS Spectrum domains, higher scores on AdAS Spectrum Inflexibility and adherence to routine and Restricted interests and rumination domains, as well as lower scores on Verbal communication domain, were statistically predictive of orthorexic symptoms. Conclusions: Our findings highlight an overlap between ON and autism spectrum psychopathology. Further studies are needed to clarify the relationship between restrictive eating disorders and female autism phenotypes.