Remember that intense high you get when you fall in love? Researchers have discovered the feeling you experience during that first flush of passion can kill physical pain in a similar way to opioid painkillers such as morphine. No wonder some people find it so addictive.
The researchers enrolled students who had recently started a new romance, and asked them to gaze at photos of the object of their affections. At the same time they subjected the volunteers to a mild dose of pain using a computer-controlled heat probe.
The scientists also measured the activity in different parts of the students' brains - specifically the areas that are involved when we feel pain. They discovered that when the volunteers looked at photos of their new lovers there was less activity in the brain's pain centres than when the photos were taken away.
The scans, say the researchers, are comparable with those of people using morphine and cocaine. However when the volunteers gazed at photos of someone they knew and found attractive - but weren't involved with - the same effect didn't apply.
The bad news is that love-induced analgesia could wear off as the early, intense passion phase inevitably settles down. But it does reinforce the idea that people who are lonely and depressed feel pain more strongly than those who feel cherished.
How has love or passion affected you in an unexpected way? We'd love to hear about it.