While a new meta-analysis of 31 studies suggests that children with autism spectrum disorders (ASD) have lower levels of oxytocin in their blood compared to neurotypical children, a separate study indicates that administering oxytocin to children with ASD does not confer any benefits.

Oxytocin is a hormone that enhances social recognition and social memory and reduces stress. Some research has suggested that administering oxytocin to individuals with ASD may reduce their symptoms.

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In the meta-analysis, Simon John and Adrian Jaeggi examined studies measuring oxytocin in plasma/serum, saliva, or cerebrospinal fluid in autistic and neurotypical individuals. The researchers found that oxytocin levels were significantly lower in individuals with ASD than in controls, and that “this overall effect was driven entirely by differences among children but not adults.”

“Our finding of lower oxytocin levels in autistic children points to an involvement of the oxytocin system in the development or manifestation of ASD,” the researchers say. “….Furthermore, in at least 19 articles, oxytocin levels were correlated with ASD symptom severity, with the majority reaching significance.” They add, “Together with studies relating oxytocin levels to socio-cognitive functions in neurotypical individuals as well as in siblings of autistic children, our finding is consistent with oxytocin levels mediating a continuous range of socio-cognitive function, at the extreme of which are autistic people.”

The researchers say that their findings regarding adults suggest that oxytocin levels in individuals with ASD might normalize as they grow older. Consistent with this possibility, they note, symptoms of autism often improve in adulthood. This could explain, they say, why intranasal administration of oxytocin in autistic adults frequently has little or no effect on symptoms.

They conclude that while more studies are needed to investigate the connections between the oxytocin system and social deficits in ASD, and to determine whether social deficits cause low oxytocin levels or vice versa, “[T]hese results support further research into the use of oxytocin to treat social deficits in children.”

A new large-scale study, however, questions the usefulness of administering oxytocin to children with ASD. Linmarie Sikich and colleagues conducted a 24-week, placebo-controlled trial to examine the effects of intranasal oxytocin therapy on children and adolescents with ASD. Subjects were between 3 and 17 years of age, and the researchers used the Aberrant Behavior Checklist and several other scales to measure outcomes.

Of the 290 children enrolled in the trial, 139 in the oxytocin and 138 in the control group completed it. The researchers say they detected “no significant between-group differences” on measures of social or cognitive functioning at the end of the trial. Sikich comments, “This is really a major setback. We were really hoping to find a benefit and just couldn’t see it anywhere.”

“Oxytocin levels tend to be lower in autistic children: a meta-analysis of 31 studies,” Simon John and Adrian V. Jaeggi, Autism, July 2021 (free online).  Address: Simon John, Institute of Evolutionary Medicine, University of Zurich, 8057 Zurich, Switzerland, [email protected]

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“Intranasal oxytocin in children and adolescents with autism spectrum disorder,” Linmarie Sikich, Alexander Kolevzon, Bryan H. King, Christopher J. McDougle, Kevin B. Sanders, Soo-Jeong Kim, Marina Spanos, Tara Chandrasekhar, Pilar Trelles, Carol M. Rockhill, Michelle L. Palumbo, Allyson Witters Cundiff, Alicia Montgomery, Paige Siper, Mendy Minjarez, Lisa A. Nowinski, Sarah Marler, Lauren C. Shuffrey, Cheryl Alderman, Jordana Weissman, Brooke Zappone, Jennifer E. Mullett, Hope Crosson, Natalie Hong, Stephen K. Siecinski, Stephanie N. Giamberardino, Sheng Luo, Lilin She, Manjushri Bhapkar, Russell Dean, Abby Scheer, Jacqueline L. Johnson, Simon G. Gregory, and Jeremy Veenstra-VanderWeele, New England Journal of Medicine, October 14, 2021 (online). Address: Linmarie Sikich, [email protected]

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“Study: ‘Sociability hormone’ didn’t help kids with autism,” Lindsey Tanner, Medical Xpress, October 14, 2021.

This article originally appeared in Autism Research Review International, Vol. 35, No. 4, 2021