Title: Power or placebo?

Key words: conventional medicine, complementary medicine, placebo effect, therapeutic relationships, physiology, endorphins, neurochemicals, naloxone, morphine, analgesia, homeopathy, acupuncture, herbalism, chiropractic,

Date: Jan 2002

Category: Materia Medica

Type: Abstract

Author: Geoff Watts



Power or placebo?

With the right encouragement, your mind can convince the body to heal itself. What is the mysterious force that conventional medicine seems to have forgotten?

Do you want to devise a new form of alternative medicine? No problem. Here's the recipe.

Be warm, sympathetic, reassuring and enthusiastic. Your treatment should involve physical contact, and each session with your patients should last at least half an hour. Encourage your patients to take an active part in their treatment and understand how their disorders relate to the rest of their lives. Tell them that their own bodies possess the true power to heal. Make them pay you out of their own pockets. Describe your treatment in familiar words, but embroidered with a hint of mysticism: energy fields, energy flows, energy blocks, meridians, forces, auras, rhythms and the like. Refer to the knowledge of an earlier age: wisdom carelessly swept aside by the rise and rise of blind, mechanistic science.

Oh, come off it, you're saying. Something invented off the top of your head couldn't possibly work, could it? Well yes, it could--and often well enough to earn you a living. A good living if you are sufficiently convincing or, better still, really believe in your therapy.

Many illnesses get better on their own, so if you are lucky and administer your treatment at just the right time you'll get the credit. But that's only part of it. Some of the improvement really would be down to you. Not necessarily because you'd recommended ginseng rather than camomile tea or used this crystal as opposed to that pressure point. Nothing so specific. Your healing power would be the outcome of a paradoxical force that conventional medicine recognises but remains oddly ambivalent about: the placebo effect.

Placebos are treatments that have no direct effect on the body, yet still work because the patient has faith in their power to heal. Most often the term refers to a dummy pill, but it applies just as much to any device or procedure, from a sticking plaster to a crystal to an operation. The existence of the placebo effect implies that even quackery may confer real benefits, which is why any mention of placebo is a touchy subject for many practitioners of complementary and alternative medicine (CAM), who are likely to regard it as tantamount to a charge of charlatanism. In fact, the placebo effect is a powerful part of all medical care, orthodox or otherwise, though its role is often neglected and misunderstood.

One of the great strengths of CAM may be its practioners' skill in deploying the placebo effect to accomplish real healing. "Complementary practitioners are miles better at producing non-specific effects and good therapeutic relationships," says Edzard Ernst, professor of CAM at Exeter University. The question is whether CAM could be integrated into conventional medicine, as some would like, without losing much of this power.

At one level, it should come as no surprise that our state of mind can influence our physiology: anger opens the superficial blood vessels of the face; sadness pumps the tear glands. But exactly how placebos work their medical magic is still largely unknown. Most of the scant research to date has focused on the control of pain, because it's one of the commonest complaints and lends itself to experimental study. Here, attention has turned to the endorphins, natural counterparts of morphine that are known to help control pain. "Any of the neurochemicals involved in transmitting pain impulses or modulating them might also be involved in generating the placebo response," says Don Price, an oral surgeon at the University of Florida who studies the placebo effect in dental pain. "But endorphins are still out in front."

That case has been strengthened by the recent work of Fabrizio Benedetti of the University of Turin, who showed that the placebo effect can be abolished by a drug, naloxone, which blocks the effects of endorphins. Benedetti induced pain in human volunteers by inflating a blood-pressure cuff on the forearm. He did this several times a day for several days, using morphine each time to control the pain. On the final day, without saying anything, he replaced the morphine with a saline solution. This still relieved the subjects' pain: a placebo effect. But when he added naloxone to the saline the pain relief disappeared. Here was direct proof that placebo analgesia is mediated, at least in part, by these natural opiates.

Still, no one knows how belief triggers endorphin release, or why most people can't achieve placebo pain relief simply by willing it. Several labs are now thinking of using brain imaging to study the neurobiology of the placebo effect in more detail. "The brain has already been imaged during drug- induced analgesia," says Price. "There's going to be a race between laboratories to do this experiment first for placebo analgesia."

Though scientists don't know exactly how placebos work, they have accumulated a fair bit of knowledge about how to trigger the effect. A London rheumatologist found, for example, that red dummy capsules made more effective painkillers than blue, green or yellow ones. Research on American students revealed that blue pills make better sedatives than pink, a colour more suitable for stimulants. Even branding can make a difference: if Aspro or Tylenol are what you like to take for a headache, their chemically identical generic equivalents may be less effective.

Special delivery

It matters, too, how the treatment is delivered. Decades ago, when the major tranquilliser chlorpromazine was being introduced, a doctor in Kansas categorised his colleagues according to whether they were keen on it, openly sceptical of its benefits, or took a "let's try and see" attitude (American Journal of Psychiatry, vol 113, p 52). His conclusion: the more enthusiastic the doctor, the better the drug performed. And this year Ernst surveyed published studies that compared doctors' bedside manners (The Lancet, vol 357, p 757). The studies turned up one consistent finding: "Physicians who adopt a warm, friendly and reassuring manner," he reported, "are more effective than those whose consultations are formal and do not offer reassurance."

Warm, friendly and reassuring are precisely CAM's strong suits, of course. Many of the ingredients of that opening recipe--the physical contact, the generous swathes of time, the strong hints of supernormal healing power--are just the kind of thing likely to impress patients. It's hardly surprising, then, that complementary practitioners are generally best at mobilising the placebo effect, says Arthur Kleinman, professor of social anthropology at Harvard University.

"This doesn't go down well in these communities because of the denigrating connotations of placebos. It's very threatening to people in those fields," Kleinman says. "The problem is that biomedicine has an extraordinarily negative view of placebos. They're treated as a nuisance rather than being seen as what they really are." And what they are, according to Kleinman, is part of the complex interaction of physiology, psychology and culture which underlies the process of turning a sick person into a healthy one.

This, needless to say, is a world away from the mechanistic approach of most conventional medicine, which has little to say about what people's experience of illness means to them. As Ernst puts it: "The very popularity of complementary medicine is a criticism of mainstream medicine. In the mainstream we have sharper and sharper tools. But in terms of empathy, time, understanding and touch we are losing out."

But even if many CAM therapies do get much of their power from the placebo effect, it's still important to ask whether there's anything more to them than that. To say--as many a CAM practitioner does--that a treatment "works" begs the question of how well it works. If a mantra-induced placebo effect will ease the pain of my bad back, that's good. But might something else do it even better? A handful of aspirin, for example? If doctors had been content to declare that a treatment works and leave it at that, orthodox medicine would not have got far. We want to know not just what works, but what works best. In answering that question, there's no substitute for clinical trials.

Yet it's not easy to design those trials in a way that both CAM advocates and conventional scientists will agree is fair. To give the clearest possible test of the treatments in question, experimentalists want to randomly assign patients to receive, say, aspirin or mantra therapy while rigorously holding all other conditions constant. But CAM practitioners charge that this cookie-cutter regularity is unfair to CAM therapies because it removes the individualised care that is such a central feature of most of them. "Because I apply orthodox research methods to complementary medicine, I've been accused of stripping it of what makes it work," says Ernst. "They say I'm throwing out the baby with the bath water. I accept that this could be a danger. If a therapy works only as a placebo then maybe one should keep science out of it. On the other hand this is how science advances."

This problem of context extends far beyond the realm of research. It also casts a shadow over attempts to integrate alternative therapies, with their powerful placebo- invoking techniques, into mainstream medicine. In practice this integration would mean, among other things, offering alternative medicine on state systems like Britain's National Health Service. To a limited but growing extent this already happens: the NHS runs a couple of homeopathic hospitals, and increasing numbers of family doctors invite aromatherapists, acupuncturists, herbalists and others into their surgeries. Some doctors even administer these treatments themselves.

But for much of CAM--especially techniques in which the placebo effect accounts for most or perhaps all the benefit--integration might well be counterproductive. After all, the value of CAM depends partly on its unorthodoxy. Price talks of a "clash of cultures". Would your free, state-registered crystal therapist, pressed for time and perhaps wearing a uniform just like other paramedical staff, still be able to mobilise as good a placebo response? Ernst, for one, doubts it, and sees this as a powerful argument against integration. "Although there is little evidence to support the view, one intuitively feels that something exotic has a stronger placebo effect than something bog standard. And some complementary therapies are very exotic," he says.

Integration faces other obstacles, too. Doctors would face serious ethical problems in recommending what they know to be placebo treatments to their patients. And complementary practitioners would likely be disparaged by their conventional counterparts, as they often are today. With the growing emphasis on evidence-based medicine, installing a roomful of radionics boxes or setting aside a clinic for dispensing Bach flower remedies would be hard to justify, however much it might please the customers. Integrated medicine "would have about as much validity as a hybrid of astronomy and astrology", Neville Goodman, an anaesthetist in Bristol, wrote in the April newsletter of HealthWatch.

Healthcare managers, too, may view such moves with some alarm. The addition of a whole raft of new and time-consuming treatments could play havoc with already overstretched budgets. In the long term, though, a few CAM techniques might achieve integration. A study of low back pain by Britain's Medical Research Council, for instance, revealed that chiropractic compares favourably with conventional hospital treatment in terms of cost and effectiveness (British Medical Journal, vol 300, p 1431). It's likely that chiropractic treatment provides specific benefits over and above the placebo effect.

Even CAM techniques that do largely depend on their placebo value could achieve the same cost-effectiveness. Indeed, for most of medicine's history, compassion, attention and tender loving care--all big contributors to the placebo effect--were all that doctors had to offer. The advent of science changed that, but in adopting their new role of body technician, doctors have to a great extent dropped the traditional one of healer: the non-specific but still valuable business of caring. Most doctors would now be faintly embarrassed by the suggestion that "healing" might be part of their job description. It sounds a bit pre-scientific. But that's what most CAM practitioners still offer, and they are certainly not embarrassed by the idea.

A professor of surgery with a confident manner, an expensive suit and an international reputation who sees you privately and guarantees to solve your problem with a costly operation may still be unrivalled as a source of placebo power. But most doctors are beaten hands down by countless alternative practitioners who might not know a lymphocyte from a lump of cheese. What they do know is how to make you feel better. And that's a big part of the battle.

An ethical dilemma

For doctors who take their medical ethics seriously, the placebo effect can pose a dilemma. Imagine that a patient turns up asking asking for advice about a remedy which is harmless but, in the doctor's view, also useless. If there's a proven orthodox cure for the complaint, the correct course of action is clear: steer the patient towards that treatment.

But suppose there is no orthodox treatment, or the patient has tried whatever there is and not responded. Should the doctor stay true to science and declare that the remedy is a waste of time, thereby undermining any beneficial placebo effect it might have? Or should scientific purity be sacrificed in favour of an enthusiastic but dishonest endorsement which might boost the treatment's placebo action? Could the doctor even argue that endorsement would be legitimate because the remedy would in fact have some benefit, thanks to the placebo effect?

In practice, many doctors try to avoid betraying either their allegiance to science or their ethical duty to tell the truth. One escape route is to find a form of words which wriggles round the problem. Something like, "I've had no first-hand experience of this treatment, but I know that some people find it rewarding." That's what you call the art of medicine.

Geoff Watts is a medical and science journalist, and author of Pleasing the Patient, a book on the placebo effect. He is also vice-chairman of the group HealthWatch, which argues the case for reliable information about medicine

From New Scientist magazine, 26 May 2001.