Pain-Related Placebo Effect Detected In Spinal Cord

Researchers in Germany found that when they treated volunteers with a placebo that they believed to be a painkiller, scans showed reduced signs of pain-related activity in their spinal cords.

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Then, like a blind trial, they told the volunteers they were applying two creams to their arms: one was a highly effective painkiller and the other one was an inactive cream that would have no effect. In fact both creams were inactive, ie both were placebos, but the researchers didn't tell them this.

The researchers then applied heat to the treated parts of the participants' arms (one part had been treated with what they believed was the effective painkiller and the other part treated with what they believed was the inactive cream).

The participants reported experiencing less pain in the areas that had been treated with what they believed was the effective painkiller.

During the trial the researchers also scanned the participants' spinal cords using functional magnetic resonance imaging (fMRI), and found that when the participants were treated with what they believed was the effective painkiller, the dorsal horn of their spinal cords, where pain is processed, showed less activity compared to when they were treated with what they believed, and indeed was, an inactive cream.