The autism diagnostic observation schedule: Patterns in individuals with anorexia nervosa

Objective: Studies have used the Autism Diagnostic Observation Schedule (the ADOS-2) in individuals with anorexia nervosa (AN), but the patterns of scores have not been assessed. We examined which subset of the ADOS-2 items best discriminate individuals with AN from healthy controls (HC), and assessed the potential clustering of AN participants based on different profiles of the ADOS-2 item scores. Method: We combined datasets from two previous studies, and (a) compared mean ranks between young AN participants (N = 118) and HC (N = 42), (ii) replicated the item selection procedure of the existing ADOS-2 algorithm to assess sensitivity of items in the AN group, and (c) applied a two-step clustering analysis in the AN group (N = 149). Results: AN participants displayed significantly higher mean ranks than HC participants in five of 32 items. All five items are part of the existing ADOS-2 algorithm. We found two clusters of AN participants; one representing normal social behaviour, comprising 68% of the individuals with AN, and one representing less efficient social behaviour, comprising 32% of individuals with AN. Conclusions: The items comprising the social affective cluster of the existing ADOS-2 algorithm are well suited to assess difficulties with social functioning in individuals with AN. Keywords: anorexia nervosa; autism spectrum disorder; psychometrics; social functioning