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The hormone oxytocin has been generating excitement — and caution — among people who care about autism.
Scientists have been eager to see if 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. 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 impact, and some research suggests that it can promote clannish and
competitive feelings, or exacerbate symptoms in people already
oversensitive to social cues. 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 include 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 the 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 Dr. 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.”
In the new study, conducted by the Yale Child Study Center,
17 children, ages 8 to 16, all with mild autism, got a spray of
oxytocin or a 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 f.M.R.I.,
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 f.M.R.I.
“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,” Dr. 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 a
continuous 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 that his last name be
witheld.
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.”
Dr. 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 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,” Dr. Dawson
said.************************
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