SANTA CRUZ, Calif. — “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 actually reduce pain. And they’ve 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. Studying the effect of love on these pathways might not only tell us more about love itself but could also help us 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.

In July 2007, the researchers started recruiting Stanford undergraduates for their 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 felt a lot less pain when they stared at their partner’s picture. And the more time students spent thinking about their partners, the greater their pain relief. Students who spent more than half of the day thinking of their significant others experienced three times more pain relief than other participants, Younger said.

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

“I could just prescribe a passionate love affair for all my patients every six months,” Mackey said. But a more realistic way for them to reduce their pain would be for them to “get out there and do something new and fun,” he said.