The primary objective of this paper was to assess the efficacy of homeopathy by systematically reviewing existing systematic reviews and meta-analyses and to systematically review trials on open-label placebo (OLP) treatments. A secondary objective was to understand whether homoeopathy as a whole may be considered as a placebo treatment. Electronic databases and previously published papers were systematically searched for systematic reviews and meta-analyses on homoeopathy efficacy. In total, 61 systematic reviews of homeopathy were included.
The same databases plus the Journal of Interdisciplinary Placebo Studies (JIPS) were also systematically searched for randomised controlled trials (RCTs) on OLP treatments, and 10 studies were included.
Qualitative syntheses showed that homoeopathy efficacy can be considered comparable to placebo. Twenty‐five reviews demonstrated that homoeopathy efficacy is comparable to placebo, 20 reviews did not come to a definite conclusion, and 16 reviews concluded that homoeopathy has some effect beyond placebo (in some cases of the latter category, authors drew cautious conclusions, due to low methodological quality of included trials, high risk of bias and sparse data).
Qualitative syntheses also showed that OLP treatments may be effective in some health conditions.
The authors concluded that, if homoeopathy efficacy is comparable to placebo, and if placebo treatments can be effective in some conditions, then homoeopathy as a whole may be considered as a placebo treatment. Reinterpreting homoeopathy as a placebo treatment would define limits and possibilities of this practice. This perspective shift suggests a strategy to manage patients who seek homoeopathic care and to reconcile them with mainstream medicine in a sustainable way.
The authors also mention in their discussion section that one of the most important work which concluded that homoeopathy has some effect beyond placebo is the meta‐analysis performed by Linde et al. (1997), which included 119 trials with 2,588 participants and aimed to assess the efficacy of homoeopathy for many conditions. Among these ones, there were conditions with various degrees of placebo responsiveness. This work was thoroughly re‐analysed by Linde himself and other authors (Ernst, 1998; Ernst & Pittler, 2000; Linde et al., 1999; Morrison et al., 2000; Sterne et al., 2001), who, selecting high‐quality extractable data and taking into consideration some methodological issues and biases of included trials (like publication bias and biases within studies), underscored that it cannot be demonstrated that homoeopathy has effects beyond placebo.
I agree with much of what the authors state. However, I fail to see that homeopathy should be used as an OLP treatment. I have several reasons for this, for instance:
- Placebo effects are unreliable and do occur only in some but not all patients.
- Placebo effects are usually of short duration.
- Placebo effects are rarely of a clinically relevant magnitude.
- The use of placebo, even when given as OLP, usually involves deception which is unethical.
- Placebos might replace effective treatments which would amount to neglect.
- One does not need a placebo for generating a placebo effect.
The idea that homeopathic remedies could be used in clinical practice as placebos to generate positive health outcomes is by no means new. I know that many doctors have used it that way. The idea that homeopathy could be employed as OLP, might be new, but it is neither practical, nor ethical, nor progressive.
Regardless of this particular debate, this new review confirms yet again:
HOMEOPATHY = PLACEBO THERAPY