Researchers in Germany have discovered a way in which the placebo effect can be used to control pain, something which could influence the way pain is treated in the future.
The team tested their theory by applying heat to the arms of volunteers. Some had been told they had been given a painkilling cream, which was, in reality a placebo.
The researchers from the University Medical Centre, Hamburg found that those who believed they had been given pain relief had less pain signals in a region of the spinal cord called the dorsal horn.
In the study, published in the journal Science, the authors said: "In line with behavioural data that show decreased pain responses under placebo, pain-related activity in the spinal cord is strongly reduced under placebo.
"These results provide direct evidence for spinal inhibition as one mechanism of placebo analgesia and highlight that psychological factors can act on the earliest stages of pain processing in the central nervous system."
They said their work was clinically significant because it "opens up new avenues for assessing the efficacy and possible site of action of new treatments for various forms of pain, including chronic pain".