Expectations about pain can affect intensity

Reported by Susan Aldridge, PhD, medical journalist

Positive thinking can be as powerful as a shot of morphine when it comes to relieving pain, says a new study.
Pain is a sensation which involves thoughts and emotions and these can affect the intensity of the experience. Researchers at Wake Forest University School of Medicine now describe experiments where a group of volunteers was exposed to different intensity of painful heat stimuli.

They were monitored by functional magnetic resonance, which shows activity occurring in the brain. Mild, moderate and severe pain signals were preceded by a seven, 15 and 30 second interval respectively. But around a third of the time, the researchers mixed the signals so that the participants did not get the pain intensity expected. This had a significant effect on what they experienced.

For example, when participants expecting moderate pain were exposed to the severe level, their pain intensity ratings were actually 28 per cent less than if they expected and received severe pain. This correlated with imaging, which showed reduced activation in the pain areas in the former situation. The reduced intensity produced by manipulating expectations has about the same impact as a shot of morphine. The findings therefore suggest that such cognitive approaches could be powerful pain relievers.

Source
Proceedings of the National Academy of Sciences online 5th September 2005