Homeopathy

Homeopathy (also spelled hom?opathy or homoeopathy) from the Greek words ??????, hómoios (similar) and ?????, páthos (suffering), is a system of alternative medicine, notable for its controversial practice of prescribing water-based solutions that in many cases do not contain chemically active ingredients. The theory of homeopathy was developed by the Saxon physician Samuel Hahnemann (1755–1843) and first published in 1796. It is growing in popularity in some areas where it is practiced today, but neither its empirical nor its theoretical foundation meets minimum scientific standards.

The scientific validity of homeopathy

The following are the main scientific issues that arise in the ongoing debate between skeptics and proponents of homeopathy:

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Homeopathic claims contradict established scientific facts

Skeptics consider homeopathy to be lacking any plausible mechanism. They often view homeopathy as a pseudoscientific remnant from the age of alchemy, when important concepts such as molecules and germs were understood poorly or not at all. In the view of modern scientists, the basic interactions of molecules are sufficient to explain all known chemical and biological phenomena, even if many processes are too complex to be understood at this time. This consensus developed during and after the formulation of homeopathy, as a result of discoveries like the size of atoms by Loschmidt in 1865, the synthesis of urea by Friedrich Wöhler in 1828, and advances in understanding many diseases.

Related Topics:
Skeptics - Alchemy - Loschmidt - 1865 - Urea - Friedrich Wöhler - 1828

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The primary criticism of homeopathy by established science is the lack of a chemical mechanism to explain how ultra-dilute solutions can retain an imprint of a molecule that no longer exists in solution. Regardless of whether the dilution medium is water or alcohol, molecular physics does not allow for imprinting of anything in a liquid medium once those molecules have been diluted to near nonexistence.

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Critics also reject homeopathic theory as being logically inconsistent. Why should only the properties of the one intended remedy be imprinted during dynamization, and not the properties of all of the impurities in the water, particularly since all of the substances in complex mother tinctures are presumably imprinted? Why should artificial shaking and swirling imprint the water, but not similar processes in nature? Why should the same information be imprinted by dynamization with alcohol or by trituration with sugar, although the properties of these substances are very different from those of water?

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Theoretical and laboratory investigation of homeopathic preparations

The main difficulty in providing scientific support for the effect of homeopathic remedies lies in the lack of mechanistic explanation for the purported effects of remedies. This is both a problem in itself and a hindrance to the acceptance of favourable clinical evidence (see below), as clinical evidence is routinely judged in relation to its prior mechanistic plausibility.

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Nevertheless there is a small-scale research effort, primarily by physicists and chemists, to try detect phenomena relating to, and provide potential mechanisms for, the purported effects of submolecular or "ultra-dilute" homeopathic preparations. In addition there are occasional results that become identified by the homeopathic community or researchers - whether or not justifiably - as relevant to homeopathy.

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The following are recent observations of anomalous properties of homeopathic preparations reported in peer-reviewed publications:

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Anomalous physical properties of homeopathic water have been observed:

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• L. Rey "Thermoluminescence of ultra-high dilutions of lithium chloride and sodium chloride" (Physica A, 2003; 323:67-74) observed physical properties that related to the original composition of the solution prior to dilution.
• Vittorio Elia and Marcella Niccoli in "Thermodynamics of Extremely Diluted Aqueous Solutions," (Annals NY Acad Sci, 1999; 827:241-248) observed differences in thermal properties between double-distilled water undergoing homeopathic serial dilution-and-succussion with no starting solvent and ones with solvent initially present;
• See also their "New Physico-Chemical Properties of Extremely Diluted Aqueous Solutions" J Thermal Analysis and Calorimetry, 2004; 75:815-836.

Immunological effects of ultradilute preparations on living cells have been observed:

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• Davenas et al. "Human basophil degranulation triggered by very dilute antiserum against IgE" Nature 1998; 333(6176):816-818 (a notorious paper made famous by Natures retraction of it soon after publication - what became know as the Benveniste affair.
• P. Belon, J. Cumps, M. Ennis, et al., "Inhibition of Human Basophil Degranulation by Successive Histamine Dilutions: Results of a European Multi-Centre Trial," Inflam Res 48 Suppl. 1, 1999:17-18.

The phenomenon of hormesis has been suggested to be a plausible mechanism for how low potency homeopathic preparations still containing molecules of the solute can work. It does not, however, address the question of the efficacy of the submolecular preparations.

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Recent theoretical hypotheses concerning mechanism of action invoke clathrates, which are non-random aggregations of solutes in solution that seem to occur also in water-alcohol mixtures such as are frequently used in homeopathy:

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• S. Dixit et al. Molecular segregation observed in a concentrated alcohol-water solution Nature 416: 829-832 (Apr 2002).
• T. Yokono et al. "Clathrate-like ordering in liquid water induced by infrared irradiation," Jap J Appl Phys 43 (2004), L1436-38.

This theory suggests physical and not chemical differences between pure water and homeopathic preparations. One predicted physical test which would tell difference is NMR. A recent study using NMR failed to distinguish between homeopathic solutions:

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• J. Anick "High sensitivity 1H-NMR spectroscopy of homeopathic remedies made in water BMC Complement Alt Med 4:15 (2004).

It is important to note that there is still no proposed mechanism for how such clathrates can invoke healing once inside the body.

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Clinical trials

A meta-analysis is a tool for aggregating and evaluating research data from a series of individual clinical trials that address a single topic, within which can be found references to individual trials. To date, specific meta-analyses of peer-reviewed publications which suggest no significant difference between placebo and homeopathy include:

Related Topics:
Meta-analysis - Clinical trial

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• Walach (1997) {{fn|12}} found that the effects of homeopathy were not significantly different from those of a placebo.
• Ernst (1999) {{fn|13}} was more ambiguous and did not find evidence of effects greater than placebo. However, he suggests that studies were not of good enough quality to point in either direction.
• Rodrigues & Moritz (2003) {{fn|14}} concluded that "ample evidence exists to show that the homeopathic therapy is not scientifically justifiable", because of serious shortcomings in terms of publication bias and lack of methodologically sound trials validating homeopathy. However, the review was published in an obscure Brazilian journal and is not considered as being very high up the evidence pyramid.
• Shang et al. (2005) {{fn|15}} state in The Lancet, a leading medical journal, that no convincing evidence has been found that homeopathy performs any better than placebo, whereas under the same evaluative criteria conventional medicine performs better than placebo, and concluded that doctors should be able to inform patients of the "lack of benefit." The trial results were derived from a comparative review of 8 trials of homeopathy verus 6 of trials of conventional medicine selected from two groups of 110 matching trials, based on predetermined criteria of internal validity that sought to extract the best-quality trials in both groups.

Reviews suggesting an effect above placebo include:

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• Linde et al (1997),{{Ref|Linde1997}} who concluded "the results of our meta-analysis are not compatible with the hypothesis that the clinical effects of homeopathy are completely due to placebo". However in his latter 1999 study this conclusion was largely withdrawn {{fn|18}} and questions have been raised about the original study{{fn|17}}.
• Linde & Melchart (1998) {{fn|10}} found that there was evidence to support homeopathy but this evidence was not very strong.
• Cucherat et al (2000) {{fn|11}} found some evidence in support of homeopathy, but (like Linde & Melchart) found that higher quality studies were more likely to disprove homeopathy.
• Kleijnen et al (1991) {{Ref|Kleijnenan}} concluded that "At the moment the evidence of clinical trials is positive but not sufficient to draw definitive conclusions because most trials are of low methodological quality and because of the unknown role of publication bias."

Persistent lack of concrete evidence of efficacy

Despite the available research, homeopathy has not been proven conclusively to work either in the clinic or in the lab, and the available research remains inconsistent and of variable quality. Another complicating factor is the claim by both sides of the debate for the existence of a publication bias: critics of homeopathy propose the likely existence of many negative trials of homeopathy that are not submitted for publication, whereas homeopaths claim that it is difficult to publish in the maintream scientific press because they present scientifically implausible conclusions.

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Skeptic James Randi has offered an award of one million US dollars to anyone who can prove the existence of anything supernatural or paranormal; Randi stipulates that homeopathy qualifies as such. The million dollars are also available to anyone who can, by any means of their choosing, tell the difference between plain water and any homeopathic remedy of their choosing. A recent attempt to win the prize was aired on the BBC science program Horizon.{{fn|7}} The Randi challenge is not specific to homeopathy, and is not a specific scientific research protocol. {{fn|20}}

Related Topics:
James Randi - US dollar - BBC - Horizon

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Having concluded that the controlled studies of homeopathy are too weak to be convincing, the skeptics must still address the widespread claims of successful treatments. These skeptics begin by pointing out that anecdotal evidence of controversial phenomena does not constitute evidence that a cure has taken place. Without control cases, it is impossible to distinguish between efficacy of a treatment and spontaneous remission. Without double blinding it is impossible to rule out observer bias and the placebo effect. Without reproduction in a separate study, it is difficult to rule out chance, fraud, or poorly understood systematic effects.

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The possibility of testing homeopathy scientifically

It is often said that homeopathy does not lend itself to being tested through statistical means because of the individualized nature of homeopathic treatment and the role of the doctor-patient relationship. But while it may be difficult to objectively study some aspects of homeopathic treatment, the efficacy of homeopathic preparations in high dilution is easily studied using standard methods of placebo control: if the placebo and treatment groups cannot be distinguished at a statistically significant level on the basis of the clinical evaluation, patient report, or objective measures, then the hypothesis of efficacy can be rejected. Indeed, homeopathic remedies are popularly used over-the-counter in an analogous manner to conventional medicines (rather than following classical-homeopathic principles), so likewise should be amenable to testing.

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Because homeopathy lacks the research infrastructure of modern medicine, but is largely clinically based, few homeopaths are properly trained in the methods of scientific research. Following a recent period of much interest in clinical support for homeopathy (possibly due to the rise of the evidence-based medicine movement, beginning in the early 1990s), many in the homeopathic community have concluded that, until a plausible mechanism-of-action is found, further clinical evidence will carry little weight, and the limited resources of the community should therefore be invested elsewhere, such as in improving educational standards. Moreover, proponents of alternative medicine often criticize the medical establishment and government agencies for failing to invest the necessary resources for testing their hypotheses thoroughly—demanding robust proof of efficacy according to the latest standards, while devoting only scant resources to the enterprise—although those that see little promise in alternative approaches often argue that such expenditure is unwarranted. Ultimately the issue becomes political, because health-care systems are subject to public scrutiny and preference. This concerns many in the scientific establishment, who regard this as a threat to the autonomy of science from political forces.

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Some researchers of homeopathy downplay the importance of the placebo effect by pointing to reports of successful treatment of infants and animals. Even in such cases, in the absence of double-blinding, practitioner bias or patient expectation may still continue to play a role.

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Yet another perspective favors the use of observational studies in place of placebo-controlled studies to compare the clinical efficacy of homeopathy to that of other methods of known efficacy. Although observational studies do not use placebo control, they have advantages such as lower cost and better modelling of clinical practice, which makes them an often-used alternative to controlled studies.

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Finally, scientific studies do not in themselves represent objective data, but have to be scrutinized and interpreted by competent scientists. While skeptics tend to reject borderline results from scientific studies, because they have a prior belief that there can be no effect (due to the lack of a plausible mechanism), proponents of homeopathy tend to accept these results due to their predisposition toward homeopathy.

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The status quo

Upwards of 130 clinical trials have been carried out investigating homeopathy or related uses of ultradilutions, mainly isopathy, and approximately 70% of these trials are in favour of some kind of efficacy above placebo{{fn|8}}. However, several meta-analyses have yielded inconclusive or unfavourable results, with two in particular observing that the higher quality trials were more likely to reject claims of efficacy over the placebo effect.

Related Topics:
Isopathy - Meta-analyses

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Linde et al (2001) {{fn|9}} summarize as such:

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In conclusion, the available systematic reviews on homeopathy provide little guidance for patients and doctors. They rather reflect the ongoing fundamental controversy on this therapy and strengthen the perception that, on one side, positive evidence from clinical trials will not convince skeptics, and that on the other side negative results from trials not representing actual practice will not have any impact on homeopaths.

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