Oxytocin therapy for core symptoms in autism spectrum disorder: An updated meta-analysis of randomized controlled trials

Background: Evidence of oxytocin for treating core symptoms in autism spectrum disorder (ASD) across development remains mixed and establishing its role is critical for guiding therapy. Aim: The current paper is aimed to include new studies and provide a stricter and updated meta-analysis to assess the oxytocin's effects on core symptoms in ASD. Method: Computerized search was conducted in PubMed, EMBASE, Cochrane Library, PsycINFO, Web of Science Database and references in reviews from the earliest date available to September 2018. Randomized controlled trials (RCTs) were identified which evaluated the effectiveness of oxytocin on at least one of two domains in patients with ASD, namely social function and repetitive behaviors. Standardized mean difference (SMD) and 95% confidence intervals (CIs) were calculated, and heterogeneity was assessed using the I² test. Results: Sixteen studies comprising 520 individuals with ASD were included in this meta-analysis. Results suggested that oxytocin had a small and non-significant effect on social function [SMD = 0.03, 95% CI (−0.19, 0.25), p = 0.781] and repetitive behaviors [SMD = 0.01, 95% CI (−0.26, 0.27), p = 0.952] compared with placebo. Studies included had a low heterogeneity (I² = 46.4%, p = 0.025 in social function; I² = 37.0%, p = 0.123 in repetitive behaviors). Conclusions: The current meta-analysis demonstrated that oxytocin had a small and non-significant effect on core symptoms in ASD population. With the limited number of included studies, more large-scale, rigorously and multi-site RCTs are needed to confirm the effectiveness of oxytocin as a treatment of ASD to acquire more convincing conclusions in the future.