Placebo: Mind over Matter in Modern Medicine. Dylan Evans
that would benefit vast numbers of future patients. Such moral calculations are notoriously difficult, and have been used to justify the most appalling crimes. Millions of Soviet citizens, for example, were encouraged to put up with draconian social policies by the officially-sponsored belief that their grandchildren would reap the rewards of their labour. Nevertheless, it is doubtful that immediate needs should always trump those of future generations. To call for the introduction of no-treatment groups in clinical trials is not to put the concerns of the disinterested scientist above those of the caring physician. The ultimate beneficiary of good medical research is the patient, not the researcher.
MIND-BODY MEDICINE
If no-treatment control groups were included in clinical trials in addition to the placebo arm, the path would be open to testing the various claims advanced for and against the existence of the placebo effect. But how could this benefit future generations of patients? Arguably, it could help to answer one of the oldest questions in the history of medicine – how much can mind-power alone help the process of physical healing?
This question goes right back to the origin of Western medicine in ancient Greece, when, in the fifth century BC, Hippocrates and his followers began to reject the supernatural explanations that had dominated previous thinking about health and disease. Instead of blaming sickness on malevolent spirits, Hippocrates argued that all disease could be traced to simple physical problems, such as imbalances in the various liquids or ‘humours’ that circulated around the body. This rejection of psychological influences on health laid the foundations for the body-centred approach of modern Western medicine. It also sowed the seeds for a fierce debate that continues to this day and which has split medicine in two.
Plato was one of the first to take issue with Hippocrates and his followers. ‘This is the great error of our day in the treatment of the human body,’ he complained, ‘that physicians separate the soul from the body.’ It was a mistake, he argued, to treat the body without also attending to the soul. Two thousand years later, the same recriminations are still frequently levelled at Western medicine. The rise of alternative and complementary medicine is simply the latest development in a protracted battle between the idea that recovery from disease is a purely physical process and the view that the mind can play a powerful role in healing.
Unfortunately, the exchanges between the proponents of these two opposed views have usually tended to generate more heat than light. Too often each side has assumed the truth of its own position without providing evidence, as if it were obvious, with the result that the position of the other side can only seem like wilful ignorance driven by a hidden agenda. The believers in alternative medicine accuse orthodox medicine of narrow-mindedness, while the sceptics see the rhetoric of the mind-cure movement as an excuse for all manner of quackery, fraud and deception. There is some truth in both of these criticisms. There have undoubtedly been many exaggerated claims advanced on behalf of faith-healing, and the American magician James Randi has exposed many so-called ‘miracle cures’ as mere illusions and conjuring tricks. On the other hand, many scientists have been too quick to dismiss the whole area of mind-body medicine without examining the evidence fairly. It is time we stepped back and attempted to apply the same scientific principles to the question of mental healing that we apply to physical therapies. Proper research into the placebo effect offers an excellent place to start. In fact, it might be just what medicine needs to heal itself.
PLACEBOS AND CANCER
The idea that the mind can cure even the most deadly diseases, including cancer, is a popular one. It’s certainly a very comforting idea, but is it true? The evidence is mixed. David Spiegel and his colleagues at Stanford University have found that taking part in group psychotherapy can help women with advanced breast cancer to survive longer, but there were no miraculous cures.18 And the mechanisms which underlie this phenomenon are probably quite different from those involved in the placebo response. Spiegel has argued convincingly that the increase in life expectancy was due mainly to the fact that participating in the group psychotherapy sessions led the women to become involved with each other socially.19 They started to visit each other’s houses, encouraged each other when they had medical problems, and visited each other in hospital. The greater social support in turn encouraged the women to make better use of medical facilities, to co-operate more with doctors, and to make greater effort to look after themselves in general. These behavioural mechanisms are very valuable, but they are a far cry from proving any direct effect of the mind on the healing system.
There is only one case recorded in the medical literature that looks like a case of the placebo response curing cancer. It was reported way back in 1957 by an American psychologist called Bruno Klopfer, and concerns a man whom Klopfer dubbed ‘Mr Wright’.20 Mr Wright had advanced cancer of the lymph nodes (lymphoma), and was expected to die within a few weeks. The various treatments of last resort – radiotherapy and an early chemotherapy agent called nitrogen mustard – could not be used because he was anaemic. While he lay in his bed, awaiting death, Mr Wright heard that a new anti-cancer drug called krebiozen was being tested at the same hospital. He pleaded with his doctor to be given some of the new drug, and his doctor gave him a shot.
Within a few days of the injection, Mr Wright was a changed man. No longer bedridden, he was walking around the ward, chatting happily with the nurses. The huge tumour masses dotted around his body had shrunk from the size of oranges to the size of golf balls. Soon after, he was released from the hospital, apparently free of malignancy.
Two months later the newspapers reported that krebiozen was worthless. Mr Wright’s tumours quickly returned, and he was back in hospital. At this point, his doctor did something that would today be forbidden; he lied to him. Suspecting that the cure had all been down to Mr Wright’s belief in the drug, the doctor told him that the newspapers were wrong, and that krebiozen was turning out to be a powerful remedy for cancer. The only reason for Mr Wright’s relapse, the doctor assured him, was that the dose he had been given came from a batch that had deteriorated somewhat while in the pharmacy. Fortunately for Mr Wright, the doctor went on, a new batch of double-strength krebiozen was due to arrive at the hospital in two days’ time. Two days later, the doctor started giving Mr Wright injections – of pure water.
Again the tumours melted away, and Mr Wright lived for a further two months without symptoms. Then another newspaper report appeared, this time announcing the final verdict of the American Medical Association: nationwide tests really had shown krebiozen to be useless. Again, Mr Wright’s tumours reappeared, and within a few days he was back at the hospital. Two days after his readmission, he was dead.
This story has been repeated many times in the literature on mind-body medicine, but it remains the only one of its kind. This in itself should make us suspicious, since, as we shall see, single cases can be notoriously misleading. True, the timing of the events is very suggestive. Both recoveries happened very shortly after Mr Wright’s beliefs about his prognosis had gone from pessimistic to optimistic, and both relapses occurred within a few days of the reverse change. But coincidences do happen.
To rule out coincidence, we would need to know what would have happened to Mr Wright if he hadn’t been treated and consequently become so optimistic. Would he still have got better anyway? Of course, we will never really know for sure. We can’t go back in time and observe what would have happened if his doctor had never given him the krebiozen or the water injections. We can, however, make an educated guess, based on what tends to happen to people with similar forms of cancer if they are untreated.
There are many forms of cancer, each with its own typical sequence of events. A few, such as lymphoma, are known to fluctuate spontaneously. In a high proportion of cases, the tumours wax and wane without any treatment at all. The fact that Mr Wright was suffering from lymphoma rather than any other form of cancer means that it is quite possible that his two brief remissions from the disease were simply spontaneous fluctuations, unrelated to the krebiozen or the water injections. The fact that the recoveries occurred just after each treatment could easily have been a coincidence.