Mind triumphs over matter

By Marek Kohn, Evening Standard

This review of Placebo: The Belief Effect appeared in The Evening Standard on 13 January 2003.

Placebo responses can be really quite unhealthy. The problem isn't the placebo effect itself, though. It lies mainly in the response to the idea that a medical treatment may work simply because the person treated believes it will. For those who mistrust orthodox medicine and resist the principles on which it rests, the placebo effect nourishes the feeling that mind is above matter. For orthodox practitioners, it is the woodworm in the desk of reason: it reminds them that they are faith healers too. The placebo effect is a profoundly subversive one.

That, however, is largely because it is known widely but not well. Many people now assume that it can work on almost any disease, from colds to cancers; in response, some revisionist researchers have dismissed it as a myth. It certainly had a founding moment fit for a legend, in a field hospital during the Second World War. Lacking morphine to treat a soldier who needed surgery, a nurse injected him with salt water: it had the necessary analgesic effect.

The anaesthetist for the operation, Henry Beecher, was profoundly impressed, and set out to make his colleagues share his awe. Although doctors had long been aware that pills have power even without drugs in them - indeed, the understanding may be as old as the practice of healing - Beecher wanted them to see placebos as much more than a sop for dissatisfied patients. To do so, he had to stretch the available evidence. Dylan Evans, a psychologist currently researching evolutionary robotics at the University of Bath, depicts this as the start of a tradition of inadequate analysis which has preserved the mystery of the placebo effect ever since.

Two particular shortcomings are the failure to make comparisons with patients left untreated, and the failure to apply "blind" procedures in which neither practitioners nor patients know who is receiving a treatment and who is getting the placebo. These considerations are difficult to resolve when the treatment does not come in a pill, but in a complex procedure like acupuncture or psychotherapy.

One group of researchers worked around the problem by getting university professors to conduct psychotherapeutic sessions. The professors' patients did as well as those treated by trained therapists.

EVANS himself is a firm believer in what he calls the "belief effect", but within firm limits. The evidence is good, he judges, that placebos may relieve pain and inflammation; there is also some evidence that they may act against ulcers, depression and anxiety. These conditions, he argues, are all related to a physiological process called the "acute phase response", which comprises swelling, heat, pain, inactivity and loss of appetite.

This is the body's standard procedure when first challenged by infection or injury. It is unpleasant, and expensive: running a temperature makes demands on the energy budget which force a suspension of other activities. Perhaps the placebo response is what happens when patients anticipate that medical help is at hand, and unconsciously excuse themselves the heroics of inflammation.

Placebo is an object lesson in considered speculation. The argument most obviously needs underpinning where pain and depression are linked, but although Evans is confident that the two kinds of misery share a common pathway, he is careful to point out that he is relying on a single study. He is enthused by evolutionary questions, but never carried away by them. Above all, he is concerned to be constructive. He uses his hypothesis to help turn the controversies about mind and body into conversations.

Through his modesty Evans achieves true clarity: an account that should prove fascinating and stimulating to expert and ordinary readers alike. But his efforts to build a rational framework for the placebo effect end up affirming the power of irrationality. For conditions that respond to based on belief, and unsupported by evidence, have the edge over orthodox medicine, which cannot claim there is anything more than sugar in the pill.

The moral of the placebo effect is that the truth hurts.