There is little doubt that the placebo effect is real, but it has always been argued that a person feels better because they think the pill is the real deal. But what if it works even when you know it's a fake?
According to Ted Kaptchuk at Harvard Medical School and his colleagues at least one condition can be calmed by placebo, even when everyone knows it's just an inert pill. This raises a thorny question: should we start offering sugar pills for ailments without a treatment?
In the latest study, Kaptchuk tested the effect of placebo versus no treatment in 80 people with irritable bowel syndrome. Twice a day, 37 people swallowed an inert pill could not be absorbed by the body. The researchers told participants that it could improve symptoms through the placebo effect.
While 35 per cent of the patients who had not received any treatment reported an improvement, 59 per cent of the placebo group felt better. "The placebo was almost twice as effective as the control," says Kaptchuk. "That would be a great result if it was seen in a normal clinical trial of a drug."
Edzard Ernst, professor of complementary medicine at the Peninsula Medical School in Exeter, UK, thinks that "the size of the benefit is too small to be clinically relevant". Kaptchuk agrees and wants to run some larger trials to get a better picture of the effect.
If a dummy pill can improve IBS, shouldn't we be exploring its effect on other ailments? "It wouldn't work on a tumour or kill microbes, but it's likely to affect illnesses where self-appraisal is important, such as depression" says Kaptchuk.
Surely now you can make a case for using a placebo when there are no other treatment options? Kaptchuk feels there is still an ethical dilemma here. "I'm against giving patients something unless it's been shown to work in that condition," he says, though the individuals concerned may feel differently.