Why love is the drug to combat pain
Love has the power to conquer physical pain, new research suggests.
Intense feelings of romantic love block pain in a similar way to morphine, a study has shown.
Scientists in the US tested the theory on 15 male and female university students who were in the passionate early stages of a love affair.
They were shown photos of their partners while a computer-controlled heat probe placed in the palms of their hands delivered mild doses of pain.
At the same time, the students had their brains scanned by a functional magnetic resonance (fMRI) imaging machine.
The study showed that feelings of love, triggered by seeing a photo of one's beloved, acted as a powerful analgesic.
Focusing on a photo of an attractive acquaintance rather than a relationship partner did not have the same benefit.
The scans revealed that the effects of love could be compared with those of morphine and cocaine, both of which target the brain's "reward centres".
Study leader Dr Sean Mackey, of Stanford University Medical Centre in California, said: "When people are in this passionate, all-consuming phase of love, there are significant alterations in their mood that are impacting their experience of pain.
"We're beginning to tease apart some of these reward systems in the brain and how they influence pain. These are very deep, old systems in our brain that involve dopamine -- a primary neurotransmitter that influences mood, reward and motivation."
Dopamine pathways are closely associated with addiction and the deep-level pain relief induced by morphine.
The scientists recruited Stanford students who were in the first nine months of a romantic relationship.
Dr Mackey said: "We wanted subjects who were feeling euphoric, energetic, obsessively thinking about their beloved, craving their presence.
"When passionate love is described like this, it in some ways sounds like an addiction. We thought, 'maybe this does involve similar brain systems as those involved in addictions which are heavily dopamine-related'."
His colleague Professor Arthur Aron added: "When thinking about your beloved, there is intense activation in the reward area of the brain -- the same area that lights up when you take cocaine, the same area that lights up when you win a lot of money."