Autism spectrum disorder and anorexia nervosa: Investigating the behavioural and neurocognitive overlap.

Autism spectrum disorder (autism) and anorexia nervosa (AN) share many clinical features. Two key neurocognitive correlates of the autistic dyad, specifically, mentalising (social impairment) and set-shifting (restricted and repetitive behaviours/interests [RRBI]) were investigated in a sample of 327 adult participants with autism (n = 100; 50 females, 50 male), AN (n = 82; 54 females, 28 male), autism and AN (n = 45; 36 females, 9 male), and 100 (50 female, 50 male) control participants from the general population. A battery of self-report (Autism Spectrum Quotient, Eating Disorder Examination Questionnaire, Reflective Function Questionnaire, and Repetitive Behaviour Questionnaire 2 - Adult version) and performance-based (Wisconsin Card Sort Task [WCST] and Penn Emotion Recognition Test [ER-40]) measures were administered online. Clinical participants reported greater mentalising difficulty, more repetitive behaviour, and displayed worse mentalising ability compared to controls, with no difference between the clinical groups. Eating disorder psychopathology predicted error (total and perseverative) rates on the WCST, while lower levels of autistic traits were positively associated with ER-40 accuracy. We provide evidence that clinical features of autism and AN might have specific neurocognitive relevance. Improved understanding of the mechanisms underlying the overlapping features of autism and AN can have critical implications for early detection and improved and tailored intervention.