WE HAVE become accustomed to the idea of placebos. No drug trial is complete without the use of a placebo, whereby half the patients receive medication and half receive nothing more than a sugared pill.
Patients who take a placebo - literally "I shall please", which makes it sound like the kind of promise you may find on a dubious card in a Soho phone kiosk - regularly find that their symptoms clear up, because of the mere thought that they have received some medication.
In that respect, illness really can be shown to be in the mind. Only if the drug is demonstrably more beneficial than the harmless placebo is the drug marketed.
In such circumstances, the advantages of a double-blind trial - where nobody knows whether Mr Smith or Ms Brown is swallowing a real or a virtual pill - are obvious, and there is no downside.
The latest example of placebos is, however, different. The use of placebo surgery for testing a treatment for Parkinson's disease means that choices become more complex. Participants in the trial have a 50 per cent chance of receiving the transplant of foetal tissue that is reckoned to help Parkinson's sufferers. …