Do blood plasma levels of oxytocin moderate the effect of nasally administered oxytocin on social orienting in high-functioning male adults with autism spectrum disorder?

Monika Althaus,Federica Calcagnoli,Yvonne Groen,Oliver Tucha,Pieter J Hoekstra,Fred C Sweep,Albertus A.Wijers,Henriette Noltes

doi:10.1007/s00213-016-4339-1

Abstract

ObjectiveThe study investigated whether baseline plasma oxytocin (OXT) concentrations might moderate the effects of nasally administered OXT on social orienting.MethodsThirty-one males with Autism spectrum disorder (ASD) and thirty healthy males participated in a double-blind placebo-controlled crossover trial. After administration of the compound, participants were viewing pictures from the International Affective Picture System that represented a systematic variation of pleasant, unpleasant and neutral scenes with and without humans. The outcome measures were a cardiac evoked response (ECR) and a cortical evoked long latency parietal positivity (LPP).ResultsMales with ASD had significantly higher plasma baseline levels than the controls. In the absence of general treatment effects, higher baseline concentrations were found to be associated with larger treatment effects, particularly in the group of males with ASD. Higher post-treatment plasma OXT concentrations were found to be associated with smaller treatment effects and larger orienting responses in the placebo situation in the group of controls.ConclusionsWe interpret our findings as suggesting that it is the central availability of OXT determining how much of the nasally administered OXT will become centrally absorbed and how much of it will become released into the bloodstream.

Highlights

Following the many studies on the role of oxytocin (OXT) in prosocial behaviour and attachment, OXT has increasingly been investigated for its role in the pathophysiology and potential treatment of the core deficits in autism spectrum disorders (ASD), especially since its nasal administration has suggested some promising results (Andari et al 2010; Guastella et al 2010)
As the present study aimed at investigating whether baseline OXT plasma levels are associated with the effect of nasally administered OXT on social orienting in healthy male adults and male adults with ASD, we have briefly summarized the main findings of the OXT treatment studies conducted on people with ASD as well as the main findings of studies investigating endogenous peripheral and central levels of OXT in a variety of clinical and nonclinical groups
As OXT plasma levels might be differentially related to centrally controlled behaviour in autistic and healthy people, we explored whether the potentially moderating effects might differ for the male adults with ASD and the healthy male adults by investigating these effects in both groups separately

Summary

Introduction

Following the many studies on the role of oxytocin (OXT) in prosocial behaviour and attachment (see Bartz et al 2011; Guastella and MacLeod 2012; Bakermans-Kranenburg and van I Jzendoorn 2013 for extensive reviews), OXT has increasingly been investigated for its role in the pathophysiology and potential treatment of the core deficits in autism spectrum disorders (ASD), especially since its nasal administration has suggested some promising results (Andari et al 2010; Guastella et al 2010). Increased cooperative interaction and self-reported feelings of trust were found after nasal administration in young adults with highfunctioning autism and Asperger’s disorder when playing a computerized ball throwing game (Andari et al 2010) These improvements in social behaviour refer to capacities of making inferences about another person’s mood or intention, i.e. to capacities that are related to having a theory of the other’s mind (ToM), the main ingredient for showing cognitive empathy Two longer-term trials have been conducted administering OXT nasally twice daily for 6 weeks (Anagnostou et al 2012) and once daily for four consecutive days (Dadds et al 2014) to adults and children with ASD, respectively Both studies found no significant change in the primary outcome measures of general social functioning and repetitive behaviours, i.e. the core features of ASD. The main conclusion by Dadds and colleagues was to be cautious in recommending nasal OXT as a general treatment for young people with autism

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Conclusion