Arnica and induction

This issue of Homeopathy features an unusual (at least for this journal) series of case histories. Unusual in that they are interpreted sceptically, as tending to show that homeopathic medicines (in this case Arnica) do not have specific effects (‘work’). These reports arise from a clinical trial of Arnica 6 & 30c for the sequelae of carpal tunnel syndrome which was reported as demonstrating that the treatment was ineffective.[ ¹ ] This trial was subject to a number of scientific criticisms,[ ² ] but also gave rise to (inappropriate) personal attacks on its authors and a number of reports from members of the public who felt Arnica had worked for them. The lead author, Professor Edzard Ernst has collected these and gives alternative possible explanations for the apparent effects[ ³ ] particularly the known pharmacological effects of unpotentised Arnica applied topically, natural course of the disease and, of course, placebo effect. The details of the cases are scanty and, like all case reports, have passed through the lens of their author's mind. The lesson which the author draws concerns the power of ‘belief, anecdotes, placebos and expectation’.

But before succumbing to howls of indignation, we should consider what this tells us about the value (or otherwise) of the case report. The first thing it demonstrates is that the case report can cut both ways: it can be negative as well as positive. If we reject the conclusions of these case reports, but accept those of other reports with positive conclusions we need to be clear about the criteria on which we are basing such discrimination. The traditional homeopathic case report is more expansive, giving far finer level of detail. But the crucial difference is that the traditional case report is not intended to prove that a particular homeopathic medicine works or does not work in a given clinical situation, an application for which the method is ill-adapted, but to illuminate its use. The relatively discursive format is usually required to allow description of the context in which the prescribing decision(s) were made and the details of the features on which the prescription was made, and which gave the reporting clinician the conviction that these features were associated with the (almost invariable favourable) clinical outcome. The format can also be used, although in homeopathy at least, rarely is, to teach negative lessons. Eric Asher's cautionary tales are an exception, but again the narrative format is required to show how the terrain concealed the clinical trap.[ ⁴ ]

• References

• 1 Stevinson C, Devaraj VS, Fountain-Barber A, Hawkins S, Ernst E. Homeopathic arnica for prevention of pain and bruising: randomized placebo-controlled trial in hand surgery. J R Soc Med 2003; 96: 60–65.
• 2 Various authors. Homeopathic Arnica. J R Soc Med 2003; 96: 204–207.
• 3 Ernst E. The benefits of Arnica: 16 case reports. Br Hom J 2003; 92: 217–219.
• 4 Asher E. Traps for young players: when the well-selected remedy fails to act. Br Hom J 2002; 91: 174–175.
• 5 Ernst E, Pittler MH. Efficacy of homeopathic arnica: a systematic review of placebo-controlled clinical trials. Arch Surg 1998; 133: 1187–1190.
• 6 Vickers AJ, Fisher P, Smith C, Wyllie SE, Rees R. Homeopathic Arnica 30x is ineffective for muscle soreness after long-distance running: a randomized, double-blind, placebo-controlled trial. Clin J Pain 1998; 14: 227–231.
• 7 Tveiten D, Bruset S. Effect of Arnica D30 in marathon runners. Pooled results from two double-blind placebo-controlled studies. Br Hom J 2003; 92: 187–189.
• 8 Milgrom L. The memory of water regained. Br Hom J 2003; 92: 223–224.
• 9 Bellavite P.Complexity and science homeopathy: a synthetic overview. Br Hom J 2003; 92: 203–212.