Jay W. Shelton

HOMEOPATHY

How it really works

Homeopathy has been around for 200 years. It excited much controversy when it was first proposed by its originator, Samuel Christian Hahnemann (1755-1843), and the same is still true today. Its popularity has risen on the crest of the current wave of enthusiasm for complementary or alternative medicine (CAM), but critics continue to say that there is no scientific basis for its alleged effectiveness.

Prometheus are well known as publishers who specialize in producing sceptical books, so it is no surprise to find that this one reaches negative conclusions about the central claims of homeopathy. That said, however, Shelton, whose background is in physics, has written a thoughtful and balanced account of the subject in which the counter-arguments are given fair play.

As Shelton freely concedes, there is no doubt that homeopathy "works", in the sense that many patients feel better for it; indeed, he thinks it is probably more effective than many other kinds of complementary medicine. However, this does not prove that the homeopathic remedies are responsible for the improvement. Shelton identifies a number of other possible causes that might be involved. These include the oft-cited placebo effect but are not confined to it. Many disorders get better by themselves, or fluctuate in severity with periods of remission; a remedy given at the right moment may receive credit it does not really deserve. And homeopaths often do other things, such as giving lifestyle advice that may be helpful. Shelton also emphasizes the psychotherapeutic element in the consultation, which I agree is important, although not everyone would regard this as distinct from the placebo factor.

Many practising homeopaths would agree with much of this, but nearly all believe that the remedy itself has an important role as well and they therefore attach great importance to remedy selection. At once we encounter the wide variations that exist in homeopathic theory and practice. Indeed, it is quite difficult to define homeopathy in any meaningful way; one could almost say that homeopathy is whatever self-styled homeopaths do. At the extreme limits this can lead to some very odd practices indeed; Shelton has a short chapter on these. I particularly liked the story of the man who cured a car with an electrical problem by writing "Electricitas 200C" [the name of a homeopathic remedy] on a piece of paper and placing this near the engine. Another homeopath has speculated that the "proving symptoms" obtained by taking a potentized preparation made from a fossilized dinosaur bone might shed useful light on the sexual behaviour (or misbehaviour) of the dinosaur concerned.

Items like these are included only for light relief, however. In his discussion of mainstream homeopathy Shelton has chosen to concentrate on "classical" homeopathy. This is certainly the right choice, at least for an American or British audience, since it is the form that such readers are most likely to encounter. But even classical homeopathy exists in various forms; in particular, it was significantly modified by James Tyler Kent. Shelton points this out, although he fails to mention the importance for Kent (and other prominent American homeopaths at the time) of the teachings of the mystic Emanuel Swedenborg.

For critics, the most controversial aspect of homeopathy is its use of high potencies. Numerous attempts to explain how these might work have been made in the two centuries that have elapsed since Hahnemann first proposed the idea, and theories have become more sophisticated recently as our knowledge of physics has increased. In several appendices Shelton reviews the hypotheses that have been advanced but finds them all to be unsatisfactory or self-contradictory. I found these appendices particularly interesting. The currently popular notion of water clusters as the vehicle of homeopathy potency gives rise to numerous paradoxes and he concludes that either no material theory of potency can be correct or else many fundamental tenets of homeopathy must be wrong. And, as others have also remarked, the possibilities of contamination of remedies (from the starting raw material, from the material and tools used in preparing the remedies, and from the air) mean that any influence of the source of the remedy would probably be swamped by extraneous influences.

He is similarly dismissive of the "provings" literature which is, theoretically, the foundation of homeopathy. In this he is not alone; a number of homeopaths have voiced similar doubts at various times (as far back as Richard Hughes, the prominent 19th-century British homeopath, in fact), and the basis of practice has always been wider than could be justified simply from provings.

Interesting though these matters are, it is the practical aspects of homeopathy that are most important to patients, and Shelton has three chapters in which he describes the process of selecting the remedy, administering it, and following up the results of taking it. Here, as elsewhere in the book, he uses plenty of direct quotations from well-known homeopaths, so he cannot be accused of falsifying their views. What emerges most clearly is the very large element of subjectivity that obtains throughout the process, although the effectiveness seems to be pretty constant whatever method is used.

Of course, if the remedies don't really do anything it makes little difference how they are prescribed, and this is really the central question for Shelton. It can only be answered by clinical research. Shelton reviews a few of the better-known clinical trials and also discusses the main meta-analyses [critical reviews] that have appeared. At least three of these have concluded that homeopathy seems to be more effective than placebo, although only to a small extent—much smaller than the high success rates reported by homeopaths themselves. But Shelton is unconvinced, for several reasons. All the different versions of homeopathy have much the same success rates; the better the quality of the study, the less likely it was to yield a positive result for homeopathy; and there have been few attempts to replicate studies.

In summary, then, Shelton finds that homeopathy is an effective form of treatment for many patients but its mechanism of action is unrelated to the remedies themselves. Being an advocate of Karl Popper's principle of falsifiability, however, he wishes to avoid dogmatism, and he expresses his conclusions with proper scientific caution.

If evidence generated after the writing of this book proves me wrong about the role of the remedies themselves, I will be delighted. When we scientists stick our necks out by making falsifiable and hence risky predictions, we enjoy the outcome no matter what happens. If we are right, we get a little ego boost. If we are wrong, we learn something we did not previously know or believe was true. Both experiences are positive.

5 June 2004