The hormone oxytocin, which has been shown to increase trust and social bonding, could also work as a treatment to relieve pain in those who suffer from frequent headaches, according to a new study.

Of patients given a dose of oxytocin as a nasal spray, 50 percent reported their headache pain was reduced by half, and an additional 27 percent of these patients reported no pain after four hours. By comparison, 11 percent of patients who were given a placebo spray said their headache pain was cut by half after four hours, and none reported complete pain relief.

All patients in the study had a condition called chronic daily headache, in which people experience at least 15 headaches a month — often severe migraines. About 6 million Americans suffer from this condition, which can be debilitating, said study researcher David Yeomans, the director of pain research at Stanford University School of Medicine. The subjects in the trial had previously not responded to any existing treatments, the researchers said.

"These are patients that have tried pretty much everything, and not much, if anything, helps them," Yeomans said.

Headache relief

Currently, only two treatments have been shown to effectively prevent headaches in people with this condition, one of which is Botox injections, said study researcher Dr. Egilius Spierings, an associate professor at Harvard Medical School who studies headache pain management. Botox was only just approved by the Food and Drug Administration for this use in October. The other treatment is a drug called topiramate.

While both of these treatments have been shown to work better than a placebo, they don't provide relief for all patients. And both have drawbacks — topiramate can affect cognition and Botox must be injected every three months to work.

While the oxytocin study is encouraging, more research needs to confirm the findings, and determine whether the treatment has long-lasting effects, the researchers said. The study included just 40 patients, half of whom received oxytocin. And the therapy was only tested on one headache, so there's no telling whether oxytocin would ward off the frequent headaches these patients experience.

Nonetheless, "I was very impressed with the findings," Spierings said. "I'm happy for this particular patient population, because it's very important that treatments are being developed specially for that group."

On average, the treatment did not start working until after four hours. And any benefit was gone after 24 hours, Spierings said.

The oxytocin treatment took longer to work than traditional migraine therapies, which usually kick in after about two hours. Because of oxytocin's apparent delayed effect, it would probably not be suitable to treat occasional migraine, because these patients would likely want something faster, Spierings said.

The researchers said oxytocin is believed to work by acting on the trigeminal nerve, which carries pain information from the head and face. Oxytocin binds to receptors in this nerve and blocks the pain signals, Yeomans said.

Warning: may cause you to want to cuddle

So far, the researchers have not seen any adverse side effects of oxytocin treatment. This is in contrast to Botox, which is a bacterial toxin and can cause serious side effects, including problems breathing and swallowing, according to the company website. "I think people would rather do a nasal spray once or twice a day everyday than [get] these injections every three months," Spierings said.

Oxytocin has garnered a reputation as the "love hormone" due to its apparent influences on social behavior. One study found it helps women bond with their children, another suggested it makes people more trusting.

That begs the question: Would oxytocin therapies for headaches need to bear warnings such as "may cause excessive trust"?

Researchers don't have the answer yet. But the social effects of oxytocin seen so far have been mild, said study researcher Dr. Daniel Jacobs, a plastic and reconstructive surgeon in San Jose, Calif. And any affects on social behavior have to be weighed against the crippling effects of daily headaches, and the side effects of strong pain medication, such as opioids, which include nausea, changes in breathing, cognitive impairment and addiction, Jacobs said.

"You always have to compare that to the psychological effects of severe head pain, or the psychological effects of alternative drug therapies," Jacobs said. "And right now, the profile with oxytocin is far superior than the alternative," he said.

The researchers plan to conduct another trial with oxytocin, this time with a more potent dose. They also hope to get a better idea of how long the effects last, Spierings said.

Jacobs and Yeomans are two of the co-founders of Trigemina, Inc., a company currently developing oxytocin as a drug for chronic daily headache.

Follow MyHealthNewsDaily staff writer Rachael Rettner on Twitter @Rachael_MHND.