From ABC Health and Wellbeing, 10 November 2013:
Over the years, the placebo has earned an unfair reputation as an instrument of medical fakery; a white lie to convince unsuspecting patients they are being treated when in fact their treatment is nothing more than a sugar pill or surgical sleight of hand.
However growing evidence suggests the placebo and its effects are far more significant in modern medical practice than many of us realised. Some are arguing that instead of viewing it with disdain, we should instead be embracing it.
The word ‘placebo’ has its origins in the Latin for ‘to please’. While its meaning has varied over the centuries, it has come to be used as the name for an inert or simulated medical therapy, such as a sugar pill, saline injection or sham procedure, that is used precisely because it is assumed not to do anything.
So if the placebo substance or procedure is truly, medically inert, how can it have an effect? Dr Damian Finniss says it’s because we expect it to.
Filling in the gaps
“What we’re really doing when we give a placebo is we’re simulating normal treatment without actually delivering a particular treatment itself,” says Finniss, a clinician and researcher at the Pain Management Research Institute, Sydney Medical School.
What therefore happens is that your brain effectively fills in the gap created by the absent medication or treatment, and does so with remarkable physiological precision.
“In the case of pain, where we’ve done a lot of research, if you give someone a morphine-like drug repeatedly, and then you switch it over to a placebo, that placebo effect that we see is mediated by morphine-like chemicals in the brain,” Finniss says.
“If you do the same thing with a non-steroidal anti-inflammatory and you give the real drug for several days and switch to a sugar tablet, that mechanism is completely different – in fact that’s mediated by our endogenous cannabinoids – even when the patient doesn’t know.”
Research also shows that, depending on what effect a placebo is expected to have, it influences different parts of the brain. If you are given a sugar tablet and told it will relieve pain, then a certain network in your brain is activated; however, if you are given a sugar tablet and told it will improve the symptoms of a movement disorder then a different network will be activated.
“So what was deemed to be very simple – that some people got better to a sugar tablet – in fact we realise there’s a highly selective series of mechanisms that are activated depending on the therapeutic context in which we receive treatment,” Finniss says. Read more.