Scientists have solved the mystery of why some people benefit from remedies that do not contain any active pain-relief ingredients. Research published in the journal Science suggests that placebos work, in part, by blocking pain signals in the spinal cord from arriving at the brain in the first place. When patients expect a treatment to be effective, the brain area responsible for pain control is activated, causing the release of natural endorphins. The endorphins send instructions to the spinal cord to suppress incoming pain signals, and patients feel better whether or not the treatment had any direct effect.

The sequence of events in the brain closely mirrors the way opioid drugs, such as morphine, work – supporting the view that the placebo effect is grounded in physiology. The finding strengthens the argument that many established medical treatments derive part of their effectiveness from patients’ expectations that the drugs will make them better. Latest antidepressant studies suggest at least 75 per cent of the benefit comes from the placebo effect. GPs also observe that patients report feeling better only days after taking antidepressants, even though the direct effects take several weeks to kick in. ‘We’ve shown that psychological factors can influence pain at the earliest stage of the central nervous system, in a similar way to drugs like morphine,’ said Falk Eippert, of the University Medical Centre Hamburg-Eppendorf, who led the study.

The Times