Thinking that a painkiller won’t ease your pain can lessen its effectiveness, a new study suggests.
Researchers at the University of Oxford looked at how people responded to a strong analgesic when they were told that it would increase, decrease, of have no effect on their pain.
They applied painful heat to the legs of volunteers, who then rated their pain. All subjects were treated with the painkiller remifentanil.
When participants were told that they were being given the drug, they reported a 41 percent reduction in pain. But when they were tricked into thinking that they were no longer on the drug, their levels of pain rose to pre-dose levels.
MRI images of the subjects’ brains showed that there was an increase of activity in the part of the brain involved in emotional processing when they were expecting pain relief, and a decrease when they expected pain.
“It’s phenomenal,” researcher Irene Tracey told the BBC. “It’s one of the best analgesics we have and the brain’s influence can either vastly increase its effect, or completely remove it.”