Characteristics of Autism Spectrum Disorders Are Associated With Longer Duration of Anorexia Nervosa: A Systematic Review and Meta-Analysis

Objective Anorexia nervosa (AN) is associated with neuropsychological characteristics such as impairments in central coherence, cognitive flexibility, and emotion recognition. The same features also manifest in autism spectrum disorders (ASD) and have been suggested to be associated with illness prolongation in AN. The purpose of this meta-analysis was to examine whether pronounced neuropsychological characteristics related to ASD are associated with illness duration in AN. Method Four databases (Medline, PsycINFO, Scopus, PubMed) were searched for eligible studies. Search terms were (a) "anorexia nervosa" and (b) "cognitive flexibility" or "set-shifting" or "central coherence" or "emotion recognition" or "theory of mind". The final sample consisted of 53 studies. Duration of AN was divided into three categories in order to investigate differences between the groups with varying illness duration. The meta-analysis was performed with Review Manager using a random-effects model. Results Deficits in central coherence, cognitive flexibility, and emotion recognition were pronounced among individuals with prolonged AN compared to those with shorter illness duration. Discussion A prolonged course of AN appears to be associated with underlying neuropsychological characteristics that are also distinctive to ASD. Neuropsychological impairments may lead to prolonged AN, and prolonged illness may contribute to the subsequent "neurological scar effect," further strengthening these impairments.