A recent study has shown that oxytocin levels and oxytocin receptor genotypes predict social impairments in children whether they are classified as having autism spectrum disorder or not. Oxytocin is a hormone that has been associated with bonding behaviors. Basically, higher oxytocin levels in the blood mean better social functioning.
Oxytocin has been known to mediate many of the behaviors that humans associate with love and bonding, such as hugging, kissing, cuddling and putting arms around another. Oxytocin has also been known to mediate aspects of labor during child birth and breast feeding after childbirth.
The aim of the recently reported study was to analyze oxytocin in both children with autism spectrum disorder and children without the disorder. The expectation was that children with autism spectrum disorder would have lower oxytocin levels compared with children who do not have the disorder since autism is known to cause significant difficulties with social interactions.
The study was carried out by scientists in the Department of Psychiatry and Behavioral Sciences and the Department of Comparative Medicine at the Stanford University School of Medicine. The study was reported in the journal Proceedings of the National Academy of Sciences. Karen Parker, who is an Assistant Professor of Psychiatry, led the research team.
The study population was comprised of children with autism (n=79), their unaffected siblings (n=52) and unrelated children without autism (n=62). All of the participants were between three years old and 12 years old. The level of oxytocin in the blood was measured and the children were given tests to diagnose whether they had autism spectrum disorder or not. Tests were also given to determine overall social ability. OXTR gene variants, which is a gene that codes for the oxytocin receptor, were also studied in the population of children who participated in the experiment.
The results from the study showed that all of the children who participated in the study that had low levels of oxytocin, even without a diagnosis of autism, had social deficits. Also, social deficits were mildest in the children with the highest oxytocin levels. A key finding was that the social skills of the children who were not diagnosed as having autism were correlated with their oxytocin levels.
The results from the study also showed that oxytocin levels were more than 85 percent inheritable. This level of inheritability would be considered high and is comparable to the inheritability of adult height. Regarding social function, the results mean that siblings tended to behave similarly. Carriers of the “G” allele of the OXTR gene were shown to have impaired affect recognition performance and carriers of the “A” allele had greater global social impairments in all groups of children tested; that is, the children with autism, their unaffected siblings and the children without a diagnosis of autism who were unrelated.
Overall, the significance of the study results is that low levels of oxytocin are associated with impaired social function whether the children have autism spectrum disorder or not. Some have suggested that oxytocin therapy; that is, providing oxytocin to the children with low levels, may be beneficial for some. This is controversial, however, because many would suggest that it is not necessarily desirable, or ethical, to manipulate oxytocin levels to standardize social functioning.
By Margaret Lutze