Scientists have been eager to see if the hormone oxytocin, which plays a role in emotional bonding, trust, and many biological processes, can improve social behaviour in people with autism. Now, the first study of how oxytocin affects the brains of children with autism finds hints of promise and also suggestions of what its limitations might be.
On the promising side, the small study, published on Monday in the Proceedings of the National Academy of Sciences, found that the hormone, given as an inhalant, generated increased activity in parts of the brain involved in social connection. This suggests not only that oxytocin can stimulate social brain areas, but also that in children with autism these brain regions are not irrevocably damaged, but are plastic enough to be influenced.
The limitations could be linked to a finding that oxytocin prompted greater brain activity in children with the least severe autism. Some experts said that this could imply that oxytocin may work primarily in less-impaired people, but others said it might simply suggest that different doses are needed.
Here we have a really clear demonstration that oxytocin is affecting brain activity in people with autism, said Dr. Linmarie Sikich, director of the Adolescent and School-age Psychiatric Intervention Research Program at University of North Carolina, who was not involved in the study. What this shows is that the brains of people with autism aren’t incapable of responding in a more typical social way.
In the new study, conducted by the Yale Child Study Center, 17 children, ages 8 to 16, all with mild autism, inhaled a spray of oxytocin or placebo (researchers did not know which, and in another session each child received the other substance).
The children were placed in a functional magnetic resonance imaging machine (fMRI) and given a well-established test of social-emotional perception: matching emotions to photographs of peoples eyes. They took a similar test involving objects, choosing if photos of fragments of vehicles corresponded to cars, trucks, and so on.
During the eyes test, brain areas involved in social functions like empathy and reward, less active in children with autism, showed more activity after taking oxytocin than after placebo.
Also, during the vehicles tests, oxytocin decreased activity in those brain areas more than the placebo, a result that especially excited some experts.
If you can decrease their attention to a shape or object so you can get them to pay attention to a social stimulus, that’s a big thing, said Deborah A. Fein, a psychology professor at the University of Connecticut.
With oxytocin, the children did not do better on the social-emotional test, unlike in some other studies.
But experts said that was not surprising, given the difficulty of answering challenging questions while staying still in an fMRI.
What I would look for is more evidence of looking in the eyes of parents, more attention to what parents are saying, less tendency to lecture parents on their National Geographic collection, Fein said.
The Yale team suggests that oxytocin may be most useful not as an ongoing treatment to enhance general social skills, but as a tool to help children benefit more from behavioural therapy or specific social experiences.
Both animal and human studies give reasons for caution. While early research found that oxytocin promoted pair bonding in prairie voles, newer studies found that giving the equivalent of several years worth of daily oxytocin to adolescent male prairie voles made them behave abnormally, bonding with strange voles rather than their partners, said Karen Bales, a psychologist at the University of California, Davis.
She said early repeated use might tell the brain to make less oxytocin than it would produce naturally.
Even if it ends up easing autistic symptoms, autism is so complex and varied that oxytocin is unlikely to work for everyone.
People with different oxytocin receptor genes may respond differently, for example. We’re still really in the early stages of understanding whether oxytocin is going to be an effective treatment for autism, Dawson said.— New York Times News Service