Thoughts on Homeopathic Drug Provings

The review in the January issue of Homeopathy[ ¹ ] by Dantas et al has generated a controversial and much needed debate on research methods in the area of Homeopathic Drug Provings (HDP) or Homeopathic Pathogenetic Trials (HPT). Are provings a quaint historical anachronism that are no longer relevant in today's research world dominated by the randomized controlled trial; or, if they are relevant today, what sort of methodological standards might be applicable?

In a homeopathic drug proving a homeopathically prepared substance is administered to healthy volunteers in order to produce the symptoms specific to that substance and thereby reveal its inherent curative powers. During a homeopathic drug proving the goal is to provoke temporary symptoms (or “artificial illness”) associated with the homeopathic medication. These symptoms then form a symptom pattern specific to that particular homeopathic substance and provides the basis for a better understanding of the possible effects of that homeopathic remedy in patients. Can this be done and how should we go about doing that?

Before recommending some solutions I would like to raise some questions about the Dantas review article and the author's subsequent comments. First, the placebo response has never been shown to be consistent or linear[ ^2,3 ] as implied by their proposal that “Symptoms (with medicine)−Symptoms (without medicine)=Symptoms (due to medicine). This sort of reasoning is likely to confound conclusions regarding placebo responders and treatment effect, not to mention non-local effects.[ ⁴ ] It is important to remember that placebo controls in clinical trials have only been used since the late 1950s,[ ⁵ ] which makes the choice of dates for this systematic review (1945–1995) somewhat odd. Second, the methodology score which only looked at randomization, blinding, inclusion/exclusion criteria and symptom selection criteria appears limited and unlikely to assess the qualitative aspects of a rigorous proving as discussed by Sherr and Quirk. The search strategy overlooked several published provings that met the inclusion criteria outlined in their paper, including one published in the British Homeopathic Journal.[ ⁶ ] And finally, canceling out the “noise” is tricky and likely to produce a clinically useless result. I know something about this after having successfully conducted a proving of Bryonia alba with 120 subjects in 1998. The only statistically significant symptom that emerged was “low back pain.”

What methods might prove useful?

Homeopathic drug provings are probably best conducted by experienced homeopathic practitioners who, in addition to their experience in homeopathy, are experienced in clinical research and in conducting homeopathic drug provings.

We have created a protocol that follows Good Clinical Practice (GCP) guidelines and has approval from an ethics commission. Since 1996 we have consistently used 35 subjects per HPT and a randomized, double-blind, placebo controlled, cross-over design with run-in period. Despite the rigor implied in the last sentence the central investigational tool in our more than sixty homeopathic drug provings has been essentially qualitative—the journal kept by each subject. The journal is kept in an open manner with the subject describing their symptoms in their own words. During the run-in phase the subject records their current state of health every day, even when no symptoms occur. The symptoms and daily state of health recorded during the run-in phase become a point from which the subject can reference changes that occur after taking the homeopathic medication or placebo. Subjects are contacted daily during the homeopathic drug proving to discuss symptoms they may be experiencing and to answer questions that arise. Symptoms are selected based on a standardize set of nine symptom selection criteria[ ⁷ ] that we developed in 1993 and have subsequently modified. Good documentation is one of the hallmarks of a successful and useful homeopathic drug proving. This extends beyond randomisation and the inclusion/exclusion criteria to often overlooked details such as a precise description of the production method of the homeopathic medication.

Methodological rigor in homeopathic drug provings has probably been lacking historically; however, GCP guidelines, ethic commissions, formal protocols, and clinical trial registries are a recent invention and one should not automatically discount the historical homeopathic proving literature for not having used tools that were not available. It is also important to recognize that the context of medical practice has changed over the years. I do not think homeopathic drug provings are likely to be useful in evaluating the effectiveness of homeopathic remedies for specific indications. In moving forward and evaluating the usefulness of provings we should combine innovative research strategies[ ^8,9 ] that respect both homeopathy and qualitative research as well as the more well known tools of quantitative research.

• References

• 1 Dantas F, Fisher P, Walach H, et al. A systematic review of the quality of homeopathic pathogenetic trials published from 1945 to 1995. Homeopathy 2007; 96: 4–16.
• 2 Kienle G.S. The Placebo Effect: Illusion, Fact, and Reality. New York, NY: Schattauer Verlag GmbH; 1995.
• 3 Glynn RJ, Buring JE, Hennekens CH, et al. Concerns about run-in periods in Randomized Trials. JAMA 1998; 279: 1526–1527.
• 4 Walach H, Sherr J, Schneider R, Shabi R, Bond A, Rieberer G. “Homeopathic proving symptoms: result of a local, non-local, or placebo process? A blinded, placebo-controlled pilot study”. Homeopathy 2004; 93: 179–185.
• 5 Beecher H.K. The powerful placebo. JAMA 1955; 159: 1602-1606.
• 6 Riley D. Original Research—veronica officinalis. BHJ 1995; 84: 144-148.
• 7 Riley D. Extracting symptoms from Homeopathic drug provings. BHJ 1997; 86: 225-228.
• 8 Signorini A, Lubrano A, Manuele G, et al. Classical and new proving methodology: provings of plumbum metallicum and piper methysticum and comparison with a classical proving of plumbum metallicum. Homeopathy 2005; 94(3): 164–174.
• 9 Walach H., Sherr J., Schneider R., Shabi R., Bond A., Rieberer G. “Homeopathic Proving Symptoms: result of a local, non-local, or placebo process? A blinded, placebo-controlled pilot study”. Homeopathy 2004; 93: 179-185.