Therapeutic effect of oxytocin and its time‐course on objectively quantified facial expression representing autistic social deficits

Abstract

Discrepancies in the efficacy between single‐dose and repeated administrations of oxytocin on autism spectrum disorder (ASD) indicate a time‐course change in efficacy. However, the hypothesis cannot be tested without a repeatable, objective, and quantitative measurement of the core symptoms of ASD. The author’s research group comprehensively examined our single‐site exploratory (n=18, crossover) and multi‐site confirmatory (n=106, parallel‐group) , double‐blind, placebo‐controlled trials of six weeks intranasal oxytocin (48IU/day) in men with ASD. The outcome was statistical representative values of the objectively quantified facial expression intensity during a semi‐structured social interaction in Autism Diagnostic Observation Schedule (ADOS) . The quantitative facial expression analyses on data from two independent clinical trials successfully detect and verify the therapeutic effect of repeated administrations of intranasal oxytocin on autistic feature in facial expressions during social interaction. Furthermore, for the first time, the recent study demonstrated a time‐course change in the efficacy : a deterioration during repetitive administration phase and a preservation during post‐treatment phase. Together with a recent study regarding neural mechanisms of deterioration of oxytocin’s efficacy, the findings are expected to promote further development of optimization of objective, quantitative, and repeatable outcome measure for autistic social deficits and to establish optimized regimen of oxytocin treatment on ASD.