The 30 Second Skinny Advocates of Homeopathy point to the way remedies are individualised to a client to explain why the blanket approach of clinical trials fail to show positive results. There have been some trials that take individualisation into account, and they don't show positive results either. Also, even with the blanket prescriptions in clinical trials you would expect remedies to outperform placeboes as some patients would get the correct remedy by chance alone.
Following a recent discussion on Twitter, I've been thinking about one of the regular criticisms that homeopath advocates make of the evidence base, and specifically the double-blind placebo-controlled randomized trial. Homeopathy, they argue, is based on individualised treatment. The DBPCRTs diagnose people with a particular condition, asthma say, and then gives them either a homeopathic remedy for asthma or a placebo. This does not represent the way in which homeopathic remedies are administered, and so therefore the information that such trials provide, that treatments are no better than placebo, is useless.
To some extent, they are right. The majority of DBPCRTs into homeopathy do follow this structure. But not all. The assumption seems to be that creating a DBPCRT that incorporates individualised treatment is impossible, but PubMed says differently. Here's one on homeopathy for eczema. Here's another that looks at individualised treatments for asthma. Neither showed an effect that was greater than placebo. It would be illogical to take these two studies and extend them to homeopathic treatment for any condition, but it does illustrate that not only are robust clinical trials possible for individualised treatment, but that such trials do take place.
It's worth noting at this stage that although such trials should be the holy grail for homeopaths, homeopaths themselves show little or no interest in running them. This is an industry worth €1.05 billion yet shows little or no interest in providing its customers with robust clinical evidence. PubMed links through to studies and articles published in the journal Homeopathy; 398 of them. Searching within these 398 for the terms "individualised randomised placebo controlled" returns two articles, neither of which are DBPCRTs in themselves. More troubling than this is that a search for "individualised" only returns 8 results, and here not all of them trials. We are told that there is no budget within that €1.05 billion for research into treatment, yet when research is done, it is, following the advocates' own logic, not homeopathy. It is always hard to take seriously the idea that homeopathy is being oppressed by a Big Pharma conspiracy, but surely these advocates must question how far-reaching their conspiracy theory needs to go if it ensures that homeopaths, researching and publishing in their own journal, do not do the necessary research to provide a solid evidence base for their treatments.
But the search for individualised trials is something of a red herring. Homeopaths explain that the reason no effect over placebo is recorded is because there was no individualisation, but what is the implication of this stance? The treatments are not selected at random; a match is sought between a particular condition and a particular remedy. The trials resulting show no effect over placebo. What homeopaths are suggesting is explicitly that patients in the treatment arm will not get a relevent treatment. What we would expect to happen in non-individualised trials is not that the homeopathic response is wiped out all together, only that it be diminished. Some people would get relevant treatment by chance alone.
Lastly and, for me, most damningly, this position casts serious doubts on the proving process. It is only natural, when faced with a treatment that has no plausible mechanism, to question how individual treatments are arrived at. Homeopathic remedies are established by a process called proving. This involves giving a remedy to a number of healthy people, while they keep journals and note any unusual responses. These journals are then examined, and common responses are noted. This essentially means that provings will only ever deal with symptoms, rather than address underlying conditions. In clinical trials, people are treating symptoms either with a placebo or a homeopathic remedy. There is, therefore, no logical reason why someone having such-and-such a symptom shouldn't respond to treatment unless that treatment is ineffective. If the treatments do not have an effect, then, at best, the proving is wrong. Given how widespread null results are in robust homeopathic research, it seems clear that the proving process itself does not work.
In summary, then, and despite fears of repeating myself, it is not enough to point at the evidence, declare it wrong, and keep going. Sooner or later, homeopaths have to realised that faith, and faith alone, drives them, because if their treatment has no plausible mechanism, has no evidence of efficacy, and if its research process is questionable, then there is nothing left but blind faith. By all means present it as such, but don't arrogantly assume that there is some truth here that science is incapable of reaching. The science is based on nothing more than a systemised treatment. If homeopathy's efficacy is fickle enough to vanish as soon as someone looks at the figures, then it's simply not a treatment worth dealing with.