Mark Ragg: Placebo possibilities

HERE’S one to force us to open our minds — a study in Neurology showing that expensive placebos are more effective than less expensive ones.

Of course, it was in one particular circumstance. Participants were 12 people with Parkinson disease who functioned reasonably well and had shown a good response to levodopa.

In this blinded randomised crossover study, participants were given either a saline injection they were told had cost $100 to manufacture, or one they were told had cost $1500. They weren’t told why the price difference existed, and they weren’t told why they were told about the price.

And they weren’t told they were being fooled until after the event — as you can imagine, ethics approval took 8 months.

The two end points were motor function (assessed blind) and brain activation, as measured by magnetic resonance imaging (MRI).

The results were impressive — and odd — although care should be taken not to overread a study of just 12 people.

Basically, there was a non-significant trend towards an improvement in motor skills with any placebo, which was not as substantial as the improvement gained after a dose of levodopa.

But interestingly, the improvement after the $1500 placebo was roughly double that gained from a $100 shot.

And for the second end point, an odd finding. The expensive placebo decreased brain activation, in the manner of levodopa, but the cheap placebo increased brain activation.

The researchers suggested this might show that the brain puts more effort in with lowered expectation of success, although that sounds like rubbish.

An alternative explanation is that brain imaging is a reasonably inexact science with lovely colour images. (As an aside, if anybody knows of a good assessment of the value of MRI across all uses, not just selected ones, in terms of cost per quality-adjusted life-year or any other reasonable measure, I’d be pleased to see it.)

But back to the main finding. People told they were using an expensive treatment not only expected to get better, but did so. They not only felt better, but performed better on the blinded assessments of motor function. Ah, the power of suggestion.

The placebo effect is not new, of course. But exploration of the qualities associated with the placebo is something different.

For example, a paper published 18 months ago in Psychosomatic Medicine showed, again in a very small group of people, that participants changing from a placebo labelled as a branded medication to a placebo labelled as a generic felt worse. They apparently associated generics with poorer quality than branded medicines, even though that doesn’t seem to be the case.

The Neurology paper opens up all sorts of ridiculous possibilities. Perhaps the copayment for GP visits would have made people feel they were getting better treatment. Perhaps Geoffrey Edelsten’s grand pianos and mink-covered examination tables had a therapeutic benefit. Perhaps the pharmaceutical industry is doing Australian patients a favour by seeking to list products on the Pharmaceutical Benefits Scheme at the highest price possible.

Seriously though, perhaps the findings reinforce the idea suggested by earlier research on placebos: that patient assessments of quality of care largely reflect bedside manner, surroundings and how they were treated as people, rather than technical expertise — that part of being a good doctor is being a good person.

Perhaps they support the shift in teaching towards a more humanistic and person-centred approach. And perhaps they reinforce the notion of medicine as art, as well as science.

Perhaps, perhaps, perhaps …
 

Dr Mark Ragg is an adjunct senior lecturer in the Sydney School of Public Health, University of Sydney.

Jane McCredie is on leave.