The Placebo Effect

The placebo can take many forms: the administration of an ointment, the taking of a sugar pill, even opening a patient for surgery but closing before undertaking a procedure. Studies have suggested they can have a beneficial effect on the patient. Why is this?

The Case of Dr Elisha Perkins

Born in Norwich, Connecticut in 1741, Dr Elisha Perkins invented the ‘Perkins Tractors’, thin metal rods that when placed over an afflicted area, seemed possessed of healing powers. Perkins, and particularly his son Benjamin, proved excellent salesmen, producing high quality leaflets extolling the virtues of his product that “drew the noxious fluids that were the cause of those afflictions.”

The popularity of the tractors spread to Europe but raised doubts in many, particularly the retired Dr John Haygarth in the UK, who doubted their therapeutic value. With the assistance of colleagues, he constructed similar appliances and applied them to five patients suffering with ailments ranging from chronic rheumatism to joint pain.

All had been ill for a number of months and four of the five reported pain relief following the application of the fake tractors. Haygarth reported the findings in his book ‘Of the Imagination as a Cause of Disorder in the Body as Exemplified by Fictitious Tractors’

He said: “I have long been aware of the great importance of medical faith. On this principle we may account for the marvellous recoveries frequently ascribed to empirical remedies, which are commonly inert drugs.” He noted that remedies were more successful when prescribed by “a famous physician rather than an inferior character.”

In essence he was describing, and attributing the success of the Perkins Tractor, to the placebo effect.

Painkiller or Placebo?

The New Scientist reported the findings of Dr Fabrizio Benedetti and the team at the University of Turin regarding their work on the painkiller CCK-antagonist. A standard double blind randomised control trial was undertaken and, as expected, the CCK-antagonist performed better than the placebo. The interpretation was therefore that CCK-antagonist proves an effective pain killer.

However, when Dr Bendetti gave the drug to volunteers without informing them what he was doing, the drug had no effect.

He said: “If it were a real painkiller, we should expect no difference compared to the routine overt administration. What we found is that covert CCK-antagonist administration was completely ineffective in relieving pain.”

What the Turin team showed was that CCK-antagonist administration in combination with patient expectancy stimulated the production of endorphins, the body’s natural painkillers. It amplified the placebo effect, the symbiotic relationship proving successful in relieving the patient’s pain.

The Physiological Effect of Placebo

Can the placebo even initiate physiological effects on the body? There is evidence that placebo can have a biochemical influence on the status of a patient. Dr Benedetti and his colleague Dr Luana Colloca also report placebos trigger dopamine in patients suffering Parkinson’s disease.

In a study undertaken in 2004, they showed that, following conditioning, individual neurons in the brain responded to a salt solution in the same way as they did to a prescribed drug given to relieve tremors. Patients that ‘felt’ better, released dopamine and their symptoms improved.

A Good Doctor

It cannot be said that that placebo works in all cases and it certainly is not an argument for non-prescription of any medical drug that has passed rigorous clinical trials. However it may be indicative that the power of support and encouragement cannot be underestimated in the course of any treatment, which could be said to be the hallmark of any good doctor.

SourcesBBC Radio 4

New Scientist

The Placebo Effect

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