Real treatment will normally provide better outcomes for the patient than use of placebos, researchers argue
Placebos have their place by helping to achieve blinding in clinical trials—but there is no evidence they are effective for clinical care, argue Australian researchers in a recent article for the MJA.
Proponents for the clinical use of placebos have suggested they are getting more effective over time, and that changing the physical appearance of the pill can help to boost results.
“It has even been suggested that subterfuge is unnecessary; placebos can be honestly described as inert and still yield important clinical effects,” said Professor Christopher Maher and colleagues from the Institute for Musculoskeletal Health at the University of Sydney.
However the view that the colour, size and shape of a placebo pill can influence its effect does not have a firm basis in science, they argue.
“A key problem is that in many studies evaluating the influence of the appearance of a placebo pill, the participants did not consume the pill or have a health condition,” they wrote.
Where the effect of the physical appearance has been tested in a few clinical studies, these have been small and yielded “inconsistent” results.
“The notion that placebo pill appearance is important is based on a very small and weak evidence base,” argued Professor Maher and colleagues.
As for recent suggestions that it may be possible for clinicians to openly describe placebos as inert, but still elicit important clinical effects – these are also based on “doubtful science”, said the researchers.
A trial that claimed five-year beneficial effects of an open label placebo, for example, apparently followed up the participants who received the open label placebo but not the control participants who did not receive the placebo.
There is ultimately no evidence that placebos have much to offer for clinical care, outside of their important role in helping to achieve blinding for clinical trials, the authors conclude.
“The recent enthusiasm for the clinical use of placebos seems driven by myths and misunderstandings,” they said.
“When administered in a blinded fashion, a placebo will provide a small effect, but the real treatment will normally provide better outcomes for the patient.
“A placebo supporter could counter that they could get a bigger placebo treatment effect by dispensing large, red, unusually shaped placebo pills, but they would be basing this on uncertain evidence.
“It may be better to dismiss placebos and instead manage patients with evidence-based treatments.”
See the full article in the MJA here