A new study has found that higher levels of the “cuddle” hormone oxytocin are linked to stronger social skills in both healthy children and in children with autism. The research is published in the journal Proceedings of the National Academy of Sciences.
It was previously believed that low levels of oxytocin were the cause of autism. The new study, conducted by researchers at Stanford University School of Medicine and Lucile Packard Children’s Hospital Stanford, reveals that a deficiency in oxytocin does not cause the disorder but that the hormone’s ability to increase social skills may still help treat a subset of autistic children.
The researchers found that higher oxytocin levels were linked to better social functioning in all three study groups: children with autism, siblings of children with autism, and children with no autistic siblings.
“Oxytocin appears to be a universal regulator of social functioning in humans,” said Karen Parker, Ph.D., assistant professor of psychiatry and behavioral sciences and the lead author of the study. “That encompasses both typically developing children as well as those with the severe social deficits we see in children with autism.”
Among all groups, children’s social skills generally correlated with their oxytocin levels. All children with autism have social deficits, but these problems were the most severe in those with the lowest blood oxytocin and mildest in those with the highest oxytocin.
“It didn’t matter if you were a typically developing child, a sibling, or an individual with autism: Your social ability was related to a certain extent to your oxytocin levels, which is very different from what people have speculated,” said Antonio Hardan, M.D., professor of psychiatry and behavioral sciences and the study’s senior author.
“The previous hypotheses saying that low oxytocin was linked to autism were maybe a little bit simplistic,” he said. “It’s much more complex: Oxytocin is a vulnerability factor that has to be accounted for, but it’s not the only thing leading to the development of autism.”
The researchers caution, however, that blood oxytocin levels may be different from levels in the cerebrospinal fluid, which they did not measure.
The researchers also studied the importance of small variations in the gene coding for the oxytocin receptor. Certain receptor variants were linked to higher scores on standard tests of social ability.
They also found that blood levels of oxytocin are highly heritable. The heritability levels are about the same as height.
“What our study hints at is that social function may be heritable in families,” Parker said.
The findings will help eventually determine whether oxytocin would be a useful autism treatment. Certain children with autism — such as the subset of kids with autism who have naturally low oxytocin levels, or those with oxytocin receptor gene variants associated with worse social functioning — might benefit most from oxytocin-like drugs.
“Autism is so heterogeneous,” Parker said. “If we can identify biomarkers that help us identify the patients most likely to benefit from a specific therapy, we expect that will be very useful.”
Source: Stanford University