Finally, some light on the ‘Pillar of Homeopathy’

The systematic review by Dantas et al of Homeopathic Pathogenetic Trials (HPTs), better known as provings, published in this issue of Homeopathy finally brings some order to ‘the Pillar of Homeopathy’.[ ¹² ] Congratulations are due to the authors of this important work, an exploratory systematic review of 156 HPTs in six languages, which reviews and criticises the methodology used in HPTs. This project, conceived by Flavio Dantas and conducted with the aid of Peter Fisher and eleven other authors from all over the world sheds, for the first time, a clear light on the complex world of HPTs. It will certainly become a solid base to develop not only a much needed consensus on minimal requirements for reporting HPTs but to update existing guidelines for HPTs.[ ¹ ]

The need to identify and incorporate into clinical practice only reliable symptoms from HPTs is fundamental to homeopathy.[ ^2,3 ] So too is Hippocrates’ first aphorism ‘Primum non nocere’ (above all, do no harm).[ ⁴ ] The first message from this review is good news: HPTs are safe, they do not cause significant harm. But the second message is negative: despite a lot of effort, it remains very uncertain that HPTs yield valid results, capable of contributing to the cure of disease. And some conclusions are paradoxical, for instance ‘reviewers overall considered 40% of the reports unreliable, yet 70% said they would apply the findings in practice’. Overall the review reveals many serious problems in the conduct and reporting of HPTs. There has been too much heterogeneity of design and too much poor reporting.

Methodological quality

The most important tool to emerge from this review is the Methodological Quality Index (MQI). Used here to assess the quality of published HPTs, the MQI could also be used as a checklist to improve the methodology of HPTs at the design stage. The four components on which the MQI is based are very important to improve methodology. Most HPTs use placebo, but some have not used it as a comparative control.[ ⁵ ] Even exclusion and inclusion criteria and criteria for selection of effects, when used, are poorly reported.[ ^6,7 ] All this results in poor reliability. If we do not describe what we mean by ‘new’ or ‘common’ symptoms or explain why some volunteers are excluded, it will be impossible to reproduce HPTs to confirm results. Even in the best HPTs the probability that new symptoms, specific to the substance being tested, have been confused with common symptoms typical of the prover, is high.

It is probable that overestimation of symptoms occurs in HPTs, and the authors convincingly report that it was the case in many of the HPTs they reviewed, linking it to overenthusiastic and conditioned observation. But underestimation of symptoms is also possible. In 9 years experience testing five substances on ninety volunteers, I have identified about 2000 pathogenetic effects. Scepticism and/or inaccurate observation was present in about a quarter of volunteers, while some supervisors excluded valid symptoms for subjective reasons. Another possible cause of underestimation is inadequate dosage and repetition in volunteers who are not highly sensitive. So far there has been very little investigation of how many doses should be given or how frequently they should be repeated. Such observations as do exist favour frequent dosing.[ ⁸ ]

This review clearly shows the great variation HPTs, and the lack of convergence between methodologies. There is no agreement even on the simplest question, the route of exposure: ingestion or sleeping with the medicine under the pillow? A small number of ‘Dream provings’ done in the Netherlands were of very low quality and gave greatly inflated estimates of the number of mental symptoms.[ ⁹ ] Can they even be considered Hahnemannian provings? They did meet the definition of HPTs used in the review, which refers to ‘exposure’ to the substance. But in my view they are not HPTs and the definition should be modified to exclude them.

Selecting substances for HPTs

The authors discuss the rationale for selection of substances to be tested in HPTs. Clearly, as they say, toxins should be the first choice as candidate substances. Choosing toxic substances is associated with advantages, including links with pharmacology and better understanding of mechanism of action. For instance symptoms detected in a recent HPTof Viscum album 30CH were probably linked with the presence of GABA in the plant.[ ¹⁰ ] This marks a return to homeopathy's roots: since its beginning substances toxic to humans have been selected for experimentation in healthy volunteers.[ ¹¹ ] But why have so few investigators attempted to confirm the results of previous provings by replicating them? We need confirmatory pathogeneses: ideally symptoms should be found in at least two HPTs before being accepted for therapeutic use. The authors give us another suggestion, new to HPTs, the use of ‘Qualitative criteria to discriminate verum from placebo’. Again, as the authors say, such methods would require validation.

These matters need to be debated and to be the subject of methodological experimentation. Only in this way will the experimental pillar of Homeopathy become a sure instrument, contributing valid knowledge to the cure of the sick.

• References

• 1 ECH Provings Subcommitee. Homeopathic Drug Proving Guidelines. Bruxelle: ECH; 2004.
• 2 Hahnemann S. Organon dell’Arte del Guarire. Como: Edizioni di Red., 1985, par. 144 (Italian translation of the sixth German Edition).
• 3 Allen T.F. Handbook of Materia Medica and Homeopathic Therapeutics (Preface 1889). Reprint Edition. New Delhi:B. Jain Publisher Pvt. Ltd., 1994.
• 4 Hippocrates, IV sec. b.C.
• 5 Sherr J. The Dynamics and Methodology of Homeopathic Proving. Malvern: Dynamis Books; 1994.
• 6 Homeopathy School of Colorado. Proving of Amethyst, www.homeopathyschool.org.
• 7 Grimes M. Enallagma carunculatum—a proving of tule bluet dragonfly. Hom Links 2005; 18 (01/05) 41-44.
• 8 Kent JT. Lezioni di filosofia omeopatica. Como: Edizioni di Red., 1986. Lezione XXVIII – La Sperimentazione. (Translated in Italian from English original edition).
• 9 Dam K. Traum-Arzneimittelprüfungen. Homöopatische Einblicke 1995; 23: 56-59.
• 10 Signorini A, et al. Proving FIAMO 2001—Viscum album: the pathogenetic picture and clinical confirmation. Proceedings of the VII Congresso Nazionale Medicina Omeopatica, FIAMO Roma, 10–12 November, 2006.
• 11 Hahnemann S. Essay for a new principle for ascertaining the curative power of drugs, and some examinations of the previous principles. Hufeland's J 1796; 2: 391.
• 12 Dantas F, Fisher P, Walach H et al. A systematic review of the quality of homeopathic pathogenetic trials published form 1945 10 1955. Homp 2007; 96: this issue. doi:10.1016/j.homp.2006.11.005.