A longitudinal study of autism spectrum disorder characteristics in adolescents with restrictive type anorexia nervosa during and after underweight

Objectives: The aim of this prospective, longitudinal study is to compare the prevalence of autism spectrum disorder characteristics in adolescents with anorexia nervosa during and after underweight. We want to determine whether increased autism spectrum disorder characteristics in adolescents with anorexia nervosa can be regarded as a trait or as a state.

Methods: 24 adolescents with anorexia nervosa completed the youth selfreport, autism spectrum quotient and a questionnaire designed by the researchers during a state of underweight and after weight recovery.

Results: Autism spectrum quotient total score and autism spectrum quotient subscale scores for attention switching, imagination and attention to detail at the time of underweight are significantly higher than after weight recovery. Linear regression modelling does not show a statistically significant association between weight gain and autism spectrum disorder characteristics, but suggests the presence of subgroups based on baseline autism spectrum quotient score. Association remains insignificant after adjusting for use of medication and youth self-report internalizing scale score and after subgroup analysis.

Conclusions: Our results indicate that autism spectrum disorder characteristics in patients with anorexia nervosa should sometimes be considered a state rather than a trait. Caution is advised when diagnosing autism spectrum disorder in patients with anorexia nervosa, especially during underweight. Despite reluctance to diagnose, we advocate further evaluation of autism spectrum disorder characteristics as they may predict a poorer outcome. Our preliminary results suggest subgroup analysis based on autism spectrum quotient score during underweight might help identify those patients in need of specific or more intensive treatment.