Study says love doesn't hurt

"One word frees us of all the weight and pain of life. That word is love."

It's been more than 2,500 years since the Greek playwright Sophocles wrote those words, but scientists have now proved that being in love can reduce pain. And they've also shown why.

Love may tap into some of our oldest brain pathways, making us feel so euphoric that we ignore pain, according to a recent study at Stanford University and the State University of New York at Stony Brook.

The scientists found that students in love felt less pain while staring at a picture of their significant others. In addition, love acted through the same brain pathway as several strong painkillers and addictive drugs, such as heroin and cocaine. Researchers hope that studying the effect of love on these pathways might tell us more about love itself and could help find ways to treat both pain and addiction.

"It was a nice connecting of the dots between what we understand of the neural systems of love and what we understand of the neural systems of pain," said Dr. Sean Mackey, chief of the pain management division at the Stanford University School of Medicine and one of the study's researchers.

Love acts on the same brain systems as any intensely rewarding experience, such as winning the lottery, said Arthur Aron, a social psychologist at SUNY Stony Brook who collaborated with Mackey.

Aron has been a "love researcher" for 30 years, but he never thought about its impact on pain until he attended a neuroscience conference five years ago and spent time with Mackey. As Aron and Mackey discussed what brain pathways they studied, they realized they were talking about the same ones. They initiated a joint research project. And in July 2007, they started recruiting Stanford undergraduates for their study.

Having so many volunteers allowed the scientists to screen for those who described themselves as intensely in love and who scored highly on a "passionate love scale," a standardized measure of romantic feelings. Additionally, the study considered only students who had been in a relationship for nine months or less, to get those with the strongest romantic feelings.

The eight women and seven men picked for the study were then subjected to "a very intense, acute pain experience," said Jarred Younger, a Stanford assistant professor who conducted the study. To inflict pain, the scientists used a heated probe on each student's hand, and slowly increased the temperature until the pain became intolerable. Students rated their pain on a scale of zero to 10, with zero being "no pain at all," and 10 being "the worst pain imaginable." Students reported considerably less pain when they stared at their partner's picture.

They also reported that the more time they spent thinking about their partners, the greater their pain relief. The participants also experienced pain relief while performing distracting word association tasks, thinking of responses to questions such as, "What are some sports that don't use a ball?"

Previous studies have shown that such distractions can reduce pain, but when the scientists compared brain images from the love and distraction tasks, "the results were very exciting," Mackey said. "Love engaged all the regions that we were hoping that it would engage. But even better, it clearly demonstrated that it works in an entirely different way than distraction."

Mackey likened the brain to a stereo receiver, with multiple amplifiers such as love and distraction. How we perceive pain depends on how high the volume is on these amplifiers, and they can work independently of each other, he said.

Understanding these powerful reward pathways could help develop pain medication with fewer side effects, or find behavioral ways to treat pain.