From abductus and abortus to zona pellucida, none of medicine's lengthy dictionary of Latinate terms is so commonly used, yet so undervalued, as the first person singular future indicative of placere, to please. "Placebo"-anglicised as a noun-means a dummy pill: something physiologically inert, the effects of which are a consequence of the taker's own expectations of benefit. By what subtle interplay of nerves and hormones the state of our minds can influence the condition of our bodies is still obscure. But the greater puzzle about the placebo effect is that while all doctors take it seriously when doing clinical research, many disregard it when treating patients who are not enrolled in a research project.
Few people outside medicine appreciate the nature or power of placebos. Dictionary definitions are not helpful. The New Shorter OED has it as: "A pill, medicine, procedure etc prescribed more for the psychological benefit to the patient of being given a prescription than for any physiological effect." In other words, a mere comforter: something to stop you worrying about problems rather than solving them.
But to suggest that they do not benefit the patient is to miss the point. Indeed, the full measure of the placebo effect is quite startling. Studies comparing active treatments with dummy pills or sham procedures consistently show that one third of patients respond in some measure to a placebo. The significance of this remarkable fact-and the potential for confusion-can be appreciated by thinking of a chronic disease for which a practitioner claims to have devised the first remedy. Suppose this person recruits a group of sufferers and treats just half of them; suppose that six weeks later, 30 per cent of the treated group-but none of the untreated group-have improved. Optimists ignorant of the placebo effect will be tempted to hail the remedy as a breakthrough. In truth, these findings prove nothing.
The right way to do the experiment is, of course, to have three groups: one treated with the remedy; one left untreated; and one given a dummy pill. If the first and third groups improve equally, the benefits of the new remedy are nothing more than the self-healing effects of the patient's desire to have something which works.
Medical researchers have known all this for years. Recognising the power of the placebo, they use elaborate procedures for discounting it. Only improvements greater than the placebo response are accepted as evidence that a new treatment is worth adopting. This is one of the factors which has shaped the design of the randomised controlled trial, the gold standard methodology by which all medicines and many non-drug treatments are now judged.
Yet the minute that most doctors switch from being a clinical scientist to an ordinary practitioner, they behave as if the placebo effect did not exist. Most take little interest in the influence of the mind, thinking only of the physical treatments they are prescribing. They even seem to forget that they themselves can exert a valuable placebo effect. A minority of doctors claim that they are willing to take the matter seriously, but don't know how. Well, they could start by reading the literature. The evidence is meagre, but it includes some real gems.
One study carried out many years ago in the US rated the benefits of a new anti-psychotic drug according to the enthusiasm with which individual doctors prescribed it. The outcome was clear: patients treated by the most enthusiastic doctors responded best. This should be no surprise; it is one of the reasons why many controlled trials are done "blind": medical staff supervising them aren't allowed to know which patients will receive the active pill and which the dummy. If they did know, the argument goes, they might unconsciously convey a greater or lesser sense of confidence to the patient, and affect the outcome accordingly.
Another neat example of a doctor-induced placebo effect dates from the late 1970s, when a couple of surgeons compared the pain-killing value of the same drug given under different conditions. Some of their patients were assured that the drug was very effective, others that it might or might not work but was worth a try. Some were given this information in a warm and personal manner, others coldly and impersonally. No prizes for guessing which patients experienced the most pain relief.
Many of those aspects of a doctor's behaviour and attitude which are most likely to act as a placebo are really nothing more than those which any patient has the right to expect of a decent, humane and caring practitioner. The fact that they might also have a useful placebo action is simply an added bonus. We have all confronted doctors who are rude, uncaring or just not sufficiently interested to raise their eyes more than briefly from the prescription pad. While we know that this behaviour is boorish, and condemn it accordingly, it might not have occurred to us that it could also be undermining the physiological benefits of whatever pills or potions are being prescribed.
Along with the paperweights and plastic biros which drug company reps hand to doctors, perhaps they could offer small wall plaques with a phrase in pokerwork or embroidery: "Placebo-I shall please."
