A New Treatment for Autism? The “Trust Chemical” Enhances Pro-Social Behavior
Emory Professor of Psychiatry Larry Young, PhD, believes that there might be a way to treat autism and other behavioral disorders by stimulating production of a hormone that enhances social behavior—the neuropeptide oxytocin.
Young's office at Yerkes sits a few floors above a vivarium filled with prairie voles, small monogamous mammals researchers use to study the neurochemistry of pair bonding and maternal bonding. "Our brain is naturally a social brain," Young says. "We look into each other's eyes. Why not the mouth, or the nose? Because the eyes increase our ability to infer the emotions of others."
Oxytocin makes the eyes more salient, drawing our attention to them to maximize the information extracted from social interactions. "This chemical mediated attunement of the social world is part of an ancient drive that originally evolved to promote maternal nurturing and bonding," Young says, but now extends more subtly into our everyday interactions. When Young was working with prairie voles, trying to decipher the chemicals that formed attachments between mates and influenced monogamy, he found that oxytocin (not to be confused with the synthetic opiate oxycontin) was essential in forming bonds between the vole pairs. Since it is involved in the regulation of social behavior, Young saw oxytocin’s potential for being useful in alleviating the social deficits associated with autism and other neuropsychiatric disorders. "So here's a hormone that increases trust, gazing into eyes, inferring emotion, the ability to remember faces, and empathy—all things that are challenging to someone with autism," says Young. "It helps to develop 'pro-social' behavior."
Young envisions oxytocin not as a daily medicine to be given to people on the autism spectrum, but as a potential catalyst to boost the effectiveness of behavioral therapies that are commonly used to improve social functioning. "Oxytocin facilitates social learning," he says. "In the prairie vole, it's learning who your partner is. In people, social reinforcement is an important component of behavioral therapies used to treat autism." While the effects "are very short-lived; lasting only a few hours, given strategically, it could really enhance social learning."
Other investigators have previously examined the impact of intranasal oxytocin (administered in a nose spray) in autistic subjects. There is evidence that administration of intranasal oxytocin has some beneficial effects as subjects do spend more time looking into eyes, and are better at reading other people’s emotions. However, Young believes that its effectiveness is limited by poor penetration of the blood brain barrier. Even in a nasal spray, not much is actually getting deep into the brain where it has its maximal effect. "Imagine if you could find a drug that would stimulate the release of oxytocin directly into the brain, like in a mother as she nurses her baby, the effect on social behavior could be much more profound than an oxytocin nasal spray" Young says.
It turns out that activation of the melanocortin 4 receptor (MC4R) agonists causes the release of oxytocin in the brain. Young and his team have shown that MC4R agonists stimulate the formation of the monogamous pair bond in prairie voles even more effectively than an injection of oxytocin into the brain. And furthermore, that bond lasts for weeks after the drug is cleared, suggesting that the social information learned while taking the drug is long lasting.
Young is collaborating with Adam Guastella in Sydney Australia on a project funded by the Simons Foundation, to determine whether MC4R agonists improve social cognition in humans in the same ways as oxytocin. He is quite optimistic that this approach has the potential greatly improve social functioning and potentially revolutionize the treatment of autism and other disorders where social behavior is compromised.
"It's quite exciting that a clinical trial to test this novel approach to improve the effects of traditional behavioral therapy is underway," says Cale Lennon, director of licensing at Emory's Office of Technology Transfer.
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