Today, enthusiasts of homeopathy celebrate the start of the HOMEOPATHY AWARENESS WEEK. Let’s join them by re-addressing one of their favourite themes: their personal experience with homeopathy.
Most homeopathy-fans argue that the negative scientific evidence must be wrong because they have had positive experiences. Whenever I give a lecture, for instance, there will be at least one person in the audience who presents such an experience (and I too could contribute a few such stories from my own past). Such ‘case reports’ can, of course, be interesting, illuminating or leading to further research, but they can never be conclusive.
This concept is often profoundly confusing for patients and consumers. They tend to feel that I am doubting their words, but nothing could be further from the truth. Their experience is certainly true – what might be false is their interpretation of it. I think, I better explain this in more detail using a concrete, published example.
After the publication of our 2003 RCT of homeopathic Arnica which showed that two different potencies have effects that do not differ from those of placebo, I received lots of angry responses from people who told me that they had the opposite experience or observed positive outcomes on their pets. In my subsequent publication in the journal ‘Homeopathy‘ entitled ‘The benefits of Arnica: 16 case reports‘, I have tried my best to explain their experiences in the light of our finding that highly diluted homeopathic Arnica is a placebo:
Sixteen case reports of the apparent beneﬁts of Arnica … raise several relevant points. Firstly, topical Arnica preparations are often wrongly equated with homeopathic Arnica, the subject of our trial. The former are herbal preparations (ie not homeopathically diluted), which have undisputed pharmacological activity. Taken orally they would even be toxic. Thus all Arnica for oral administration must be highly diluted and has therefore no pharmacological effects. The case reports show that many lay people seem to be unclear about the difference between herbal and homeopathic Arnica.
Secondly, if animals seem to respond to homeopathic Arnica, as claimed in several of the case reports, this is not necessarily a proof of its effectiveness. Animals are not immune to placebo effects. Think of Pavlov’s experiments and the fact that conditioning is clearly an element in the placebo response.
Thirdly, the natural history of the condition can mimic clinical improvement caused by therapy. Many of the 16 cases summarized can be explained through a placebo response or the natural history of disease or the combination of both phenomena…
Many of the letters I received were outspoken to say the least. The authors stated that they were ‘appalled’, ‘saddened and angry’ by our research. Others implied that I was paid by the pharmaceutical industry to abolish homeopathy in the UK. One person felt that ‘it is highly irresponsible to dismiss a natural healing remedy with no evidence at all’. I believe the case reports … convey an important message about the power of belief, anecdotes, placebos and expectation.
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The thing about case reports and personal experiences is quite simply this: they may seem almost overwhelmingly convincing, but they can NEVER serve as a proof that the treatment in question was effective. The reason for this fact could not be more simple. Any therapeutic response is due to a complex combination of factors: placebo effects, natural history of the condition, regression to the mean, etc.
See it this way: you wake up one morning with an enormous hangover. You try to identify the cause of it. Was it the beer you had in the pub? The wine you drank before you went out? Or the whiskey you consumed before you went to bed? Perhaps you think it was the Cognac you enjoyed at a friend’s house? Only one thing is for sure: it was not the glass of shaken water you drank during the night.