From Our 2010 Archives

Oxytocin More Than Mere 'Love Hormone'

Hormone Boosts Trust, Empathy, Charitable Donations; Reduces Anxiety and Stress, New Research Shows

By Kathleen Doheny
WebMD Health News

Reviewed by Laura J. Martin, MD

Nov. 15, 2010 (San Diego) -- The love hormone oxytocin, known to be plentiful in lactating women and released by men and women during orgasm, appears to do much more, according to new research presented here at the annual meeting of the Society for Neuroscience.

It's also associated with boosting trust and empathy -- to the point of increasing the wish to donate to charitable causes -- and reducing anxiety and stress. It may also improve social functioning in people with autism, although research is scant on that.

One thing's clear: It's no longer just the ''cuddle hormone," says Margaret McCarthy, PhD, a researcher at the University of Maryland School of Medicine who moderated a news conference Sunday that summarized the latest research.

Oxytocin Boosts Happiness

The higher your oxytocin, the higher your happiness and well-being, at least for women, says Paul Zak, PhD, a researcher at Claremont Graduate University in Claremont, Calif.

To test the link, he recruited 60 female college students and drew blood samples before and after they each received a $24 gift from a stranger. The women could return a portion of the money to the stranger or not.

Before the experiment, the women also finished a survey about their general disposition and satisfaction with life.

The women who showed a higher increase in oxytocin after receiving the money were the ones likely to say they were satisfied with their lives and shared the most money with the strangers. They also tended to be more trusting.

Oxytocin is known to be important in trust, Zak says.

"Those with higher oxytocin had more sex with fewer partners," he says, reflecting more long-lasting relationships. They were likely to be liked by other people.

But it's yet to be determined whether the oxytocin makes people happy, he says, or that happier people just have more oxytocin.

And what about men? "We don't think [these findings] will generalize to men," he says.

Oxytocin May Make you a Do-Gooder

If you're unable to resist a public service announcement for a worthy cause and find yourself dashing for your wallet, perhaps you should credit -- or blame -- oxytocin.

In another study, Zak focused on men and found that men treated with the love hormone were more generous after watching public service ads.

The study included 41 men, assigned to the hormone group or the placebo group. "We used two teaspoons of oxytocin up the nose," he says.

Next, the men watched 16 public service ads on such topics as global warming, smoking, and drunk driving.

The men were asked to tell how they felt about the people in the ads and the causes. They were asked how they would feel about donating to the cause. Next, Zak says, they employed the Jerry Maguire theory to research: "Show me the money."

"Those on placebo donated to 21% of the ads, those on oxytocin 33%," he says.

Men given the hormone donated 56% more money to the causes than men in the placebo group.

Oxytocin, Zak says, "seems to control the balance between self and others in the brain."

Zak says advertisers are onto the power of oxytocin. "Why are puppies in toilet paper commercials?" he asks. Because pitchmen know people feel good about puppies -- hopefully so good their brains will release oxytocin. That, he says, can make them more likely to buy the product.

Oxytocin, Anxiety, and Friends

If oxytocin is coupled with social contact, it can relieve anxiety better than the hormone alone, says researcher Jason Yee, PhD, of the University of Illinois at Chicago.

That's true in animals, at least, as Yee and his colleagues studied the effect of oxytocin and a buddy on calming anxious prairie voles. The animals are known for forming strong, monogamous bonds. Yee stressed them briefly, gave all oxytocin to reduce anxiety, and then compared the recovery from the stress in animals who recovered alone and in those that recovered cuddling with another animal.

Those in the buddy system group exhibited less anxious behavior, in this study defined as trying to escape from the cage.

Oxytocin to Improve Social Cues?

Other animal studies have shown that oxytocin plays a role in bonding and social relationships, helping to explain why some animals are highly social and form long-lasting bonds, according to researcher Larry Young, PhD, of Emory University in Atlanta.

He cited human research that has found improved social function in people with autism after treatment with the hormone. In the future, targeting the oxytocin system in people with autism may be useful, he says, especially when combined with behavioral therapy.

Oxytocin: Perspective

Despite some of the promising new findings, another expert attending the news conference offered a caveat about oxytocin for autism treatment. "People are trying to treat autistic kids [with oxytocin] in the absence of [definitive] research," says Sue Carter, PhD, professor of psychiatry at the University of Illinois at Chicago.

Parents buy the hormone over the Internet, she says. Not a good idea, she warns. "We have no idea what the long-term consequences are,'' she says. Using oxytocin is not like using a typical drug, she says. "It's a biological stimulation model, not a pharmaceutical model." And there could be a cascade effect, she says.

SOURCES: Neuroscience 2010, San Diego, Nov. 13-17, 2010.Sue Carter, PhD, professor of psychiatry, University of Illinois, Chicago.Margaret McCarthy, PhD, University of Maryland School of Medicine.Paul Zak, PhD, Claremont Graduate University, Claremont, Calif.Larry Young, PhD, Emory University, Atlanta.Jason Yee, PhD, University of Illinois, Chicago.

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