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 behavior in people with autism. Some parents of children with autism have asked doctors to prescribe it, although it is not an approved treatment for autism, or have purchased lower-dose versions of the drug over the counter.
Scientifically, the jury is out, and experts say parents should wait until more is known. Importantly, nobody knows if oxytocin is safe or desirable to use regularly or long-term.
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 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.”
Nonetheless, said Sikich, who will be leading a large federally funded trial of 300 children to evaluate behavioral effects of daily oxytocin for six or 12 months, “there’s still a big gap in knowing how much it will really change overall functioning and how to best use it.”
Some studies suggest that oxytocin, sometimes called the “love hormone,” improves the ability to empathize and connect socially, and may decrease repetitive behaviors. Others find little or no effect, and some research suggests that it can promote clannish and competitive feelings, or exacerbate symptoms in people already oversensitive to social cues.
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, an fMRI, and given a well-established test of social-emotional perception: matching emotions to photographs of people’s 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 researchers did study oxytocin’s effect on such social interactions and are analyzing those results for later publication, said Ilanit Gordon, a co-author of the study.
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 behavioral therapy or specific social experiences.
Several experts agreed.
“Most people believe that these drugs will not immediately improve social behavior or improve some of the more negative symptoms,” said Geraldine Dawson, director of the Center for Autism Diagnosis and Treatment at Duke University.
Instead, “Think of this as possibly priming the brain to make it more receptive to social information,” she said. “This may help to enhance that child’s response to behavioral therapy and early intervention, and may not have to be used long-term.”
The Yale study includes another intriguing result: that children whose saliva showed higher oxytocin concentrations had more activity in the amygdala. That, experts said, may eventually mean that a simple saliva test could help identify who might benefit most from oxytocin.
One participant in the Yale study, Jesse, then 15, said he could tell immediately which spray was oxytocin because he became giggly, “laughing uncontrollably — it was like they gave me laughing gas.” The effects did not last long, said Jesse, whose parents asked a reporter to withhold his last name.
Since then, his parents started buying low-dose over-the-counter oxytocin spray, which they keep at home and with the high school nurse. Occasionally, when Jesse, who has Asperger’s syndrome, has a “panic attack or spiraling, it just sort of shuts off that mood, and it doesn’t come back,” said his mother, Jackie.
Or, as Jesse described it, when “I’m really stressed or sad, pretty quickly I start feeling a lot more calm. It sort of disrupted the thoughts that were making me nervous.”
Gordon does not recommend such use.
“I don’t want a wave of parents now giving their children oxytocin,” she said. “We’re not seeing that giving oxytocin equals treating autism, not yet.”
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, who conducted the research.
She said early repeated use might tell the brain to make less oxytocin than it would produce naturally.
A study of healthy men found that inhaling oxytocin made them more biased against outsiders. And when people with borderline personality disorder took oxytocin, they became more distrustful, possibly because they were already socially hypersensitive.
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.