I enjoyed parts of this evening’s One Show on BBC One. I enjoyed the explanation of the magical thinking (like cures like) and diluting ‘active’ ingredients out of existence that form the basis for homeopathy. I especially enjoyed the Doctor pointing out – in response to Monty Don’s argument that ‘it doesn’t matter how homeopathy might work’ – that homeopathy simply doesn’t work. There was one thing that really bugged me though – an anecdote offered by one of the presenters, Alex Jones.
Apparently, her friend’s psoriasis cleared up following use of a homeopathic product. I wonder how much Alex Jones knows about the placebo effect. I’d also be interested to learn whether she is aware of the following:
Spontaneous improvement, fluctuation of symptoms, regression to the mean, additional treatment, conditional switching of placebo treatment, scaling bias, irrelevant response variables, answers of politeness, experimental subordination, conditioned answers, neurotic or psychotic misjudgment, psychosomatic phenomena, misquotation, etc. [Kienle and Kiene, 1997 – PDF]
Personally, I find it much more plausible that a perceived improvement might be due to the placebo effect or one of the factors mentioned by Kienle and Kiene than the idea that such an improvement can be put down to swallowing a magic sugar pill containing no active ingredient. I don’t consider “asking the patient” to be a good way of finding out whether a treatment works.
Magical thinking: Hahnemann’s Law of Similars – “He believed that by using drugs to induce symptoms, the artificial symptoms would stimulate the vital force, causing it to neutralise and expel the original disease and that this artificial disturbance would naturally subside when the dosing ceased.” It’s like magic. Sympathetic magic. And let’s not forget, these are the same people who think writing the name of a remedy on a piece of paper can cure you – homeopathic paper remedies – and have produced ‘remedies’ made from Berlin Wall and a bit of wood taken from a shipwreck.
Dilution: Homeopathy – there’s nothing in it. 13C: “If pure water was used as the diluent, no molecules of the original solution remain in the water.” 30C: “Dilution advocated by Hahnemann for most purposes: on average, this would require giving two billion doses per second to six billion people for 4 billion years to deliver a single molecule of the original material to any patient.”
Evidence: Some scientists are willing to spend their time trawling through all the research into homeopathy and producing a systematic review of the literature. One such paper (Shang et al) can be found here. There are several Cochrane reviews of homeopathy and there is actually a systematic review of systematic reviews of homeopathy:
…there was no condition which responds convincingly better to homeopathic treatment than to placebo or other control interventions. Similarly, there was no homeopathic remedy that was demonstrated to yield clinical effects that are convincingly different from placebo. It is concluded that the best clinical evidence for homeopathy available to date does not warrant positive recommendations for its use in clinical practice.
Other interesting links: with regard to my comments on whether ‘asking the patient’ is a good way to find out if a treatment works, readers might find the slides from page 11 onwards of this PDF relevant and of interest. They come from a talk Edzard Ernst once gave at Bradford University: Trick or Treatment.
ETA: you can catch the episode on iPlayer here – link (I think it will be up for the next week or so). Sceptical Banter has also blogged about the episode (there’s a couple of useful / interesting links in the update at the bottom of the post).