1. Intranasal oxytocin was shown not to impact social interaction scores in children and adolescents with autism spectrum disorder (ASD).
2. Other measures of social function and IQ did not differ between intranasal oxytocin and placebo groups.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Based on animal models and genetic studies, the neuropeptide oxytocin was associated with social functioning and its deficiency linked to ASD. These findings led to trials of intranasal oxytocin as a treatment for ASD, which yielded inconsistent evidence of its benefits, due to various factors such as insufficient power and study design variations. As such, this trial assessed the efficacy of oxytocin in improving social function in children and adolescents with ASD. Across the trial period, no significant differences were observed in the primary social interaction measure using the Aberrant Behavior Checklist modified Social Withdrawal subscale (ABC-mSW) between the two groups. Similarly, no difference was seen in secondary outcomes for social functioning and IQ. The study’s main limitations include the use of the ABC-mSW, which has not been validated, and the flexible-dose strategy for oxytocin. Overall, the trial results did not show improvements in social interaction or function from intranasal oxytocin treatment in pediatrics with ASD and thus, did not support its therapeutic use.
In-Depth [randomized controlled trial]: This double-blind randomized placebo-controlled trial enrolled 290 children and adolescents with ASD, as defined by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5). Participants between the ages of 3 to 17 years who met diagnostic criteria and with English-speaking guardians were included in the study. Exclusion criteria included concurrent Rett syndrome, deafness, blindness, and previous daily oxytocin treatment. Participants were randomized in a 1:1 ratio to either receive daily intranasal oxytocin or matching intranasal placebo, respectively. Dosing was flexible, starting at 8 international units (IU) and escalating the target dose to a maximum of 80 IU. The trial length was 24 weeks, with periodic assessment every 4 weeks. The primary outcome was the least-squares mean change from the baseline ABC-mSW score at week 24, with higher scores indicating less social interaction. Across the trial, the least-square mean change from baseline in ABC-mSW was -3.7 points in the oxytocin group and -3.5 points in the placebo group (least-square mean difference, -0.2; 95% confidence interval [CI], -1.5 to 1.0; P=0.61). No appreciable difference was demonstrated within different verbal fluency groups, either. The least-squares mean change from baseline in Sociability Factor was -7.7 points in the oxytocin group and -8.3 points in the placebo (difference, 0.6; 95% CI, -1.8 to 3.1). Aside from a serious adverse event of sedation while driving from oxytocin, the incidence of adverse events was similar across the two groups. Overall, the study showed no appreciable benefits of intranasal oxytocin in social functioning and IQ in children and adolescents with ASD.
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