Homoeopathy: is it all bad?
There has been much discussion in the blogosphere and the Twittersphere lately about homoeopathy, partly because of some Early Day Motions being put before the British parliament on the subject, and partly because of the BMA's vote against homoeopathy at their recent conference.
Now, this may come as a surprise to anyone who is familiar with my views on homoeopathy, but I'm going to mount a partial defence of it here.
Don't worry, I haven't completely taken leave of my senses. Let's start by being clear about the scientific basis of homoeopathy: it has none. There are some people who believe that diluting a substance until it is so dilute that there is absolutely none of the original substance left confers magical powers on the water you used for the dilution. Some may say that those people reject the paradigm of Popperian critical rationalism on which mainstream science is based, opting instead for a more sociologically based paradigm of individual existentialism, although personally, I prefer to say that they're just talking complete bollocks. If anyone isn't familiar with just how much bollocks the supposed science behind homoeopathy really is, Richard Dawkins has a nice video explanation of it here.
Much clinical research has been done on homoeopathy. Occasionally, people have found that it is effective, although that's mainly because of poor study design, for example lack of randomisation or blinding, that biases the study in favour of homoeopathy. Even with impeccable study design, if enough studies are done comparing homoeopathy with placebo, you would expect some to show benefits of homoeopathy just by chance, and supporters of homoeopathy may leap on those as evidence that homoeopathic magic potions really do have magical powers. However, if you look at the totality of the evidence (there's a good review here), the message is pretty clear: homoeopathy is no better than placebo. Not at all surprising really, because homoeopathic remedies are pharmacologically inert. They are placebos, so obviously they're no better than placebos.
So to repeat, homoeopathic remedies have no active substance in them, they have no scientific basis, and they are no better than placebo.
So why do I say I'm defending homoeopathy? Well, it may be no better than placebo, but of course it is also no worse than placebo, and placebo can actually be quite effective.
With many medical conditions, if you give a patient a placebo, the patient will get better. There are two quite distinct reasons why that may happen, and it's important to be aware of the difference. The first is that the patient may simply get better anyway because of the natural history of the disease. A good example would be the common cold. Most people who have a common cold recover within a few days. So, if you give patients with the common cold a placebo treatment, they will get better. But they would have done anyway, so this is not a true placebo effect. The true placebo effect is when a patient's expectation of benefit from treatment causes some physiological change which really does make them better. A good example of this would be patients with depression. Many patients with depression show dramatic improvements on placebo treatment, and indeed a recent paper in JAMA concluded that antidepressants offer little additional advantage over placebo for milder forms of the disorder.
Now, clearly giving placebo treatment is inappropriate if proven effective treatments exist. When homoeopaths offer to protect children against measles by giving homoeopathic treatments as an alternative to vaccination, that is mind-bogglingly irresponsible, and anyone who does so deserves the strongest condemnation, and possibly even locking up. Same goes for homoeopaths who offer to treat cancer homoeopathically as an alternative to potentially curative surgery.
But there are many conditions for which placebo is a reasonable treatment option. Mild depression is an obvious example, but there are many others. Plenty of gastrointestinal complaints have no obvious treatable cause, and yet can respond to placebo treatment. Placebo treatment has the advantage of being cheap and safe, so in those cases where the efficacy is as good as any conventional treatments (ie because no effective conventional treatments are available), you can make a very good case for prescribing it.
The trouble is that you get into very difficult ethical territory if you knowingly prescribe placebo. What do you say to the patient? It's hard to imagine that many patients would be impressed if you said "Here is a placebo pill. It is totally lacking in any medicinal properties, but if you believe in it, it might make you better." That, however, is the only truly honest thing that you can say when prescribing a placebo, but that honesty probably destroys any chance of the placebo effect working. Perhaps if you prescribe a placebo and tell the patient that it is a highly effective treatment then the patient will improve. However, that is dishonest. Trust is very important in the doctor-patient relationship, and it is not hard to see trust being very quickly destroyed by such practices.
Does homoeopathy offer a way round this problem? Homoeopathy is a placebo. It is also quite an effective placebo: the strength of the placebo effect depends on many factors, but one of them is the strength of the relationship between patient and healer. As homoeopaths typically spend far longer in consultation than conventional doctors, that relationship is stronger, which helps to maximise the placebo effect.
So is homoeopathy a reasonable way to prescribe placebos in those circumstances where placebos are justified? This is where it starts to get really tricky, and I'm honestly not sure exactly what I think about the ethics of this situation. Do you nicely circumvent the ethical problems normally inherent in prescribing placebo by calling a placebo a homoeopathic treatment? Or is that just as dishonest, given that we know that homoeopathic treatments really are placebos?
If you believe that telling patients who might benefit from placebo that a homoeopathic treatment may help them is ethical, then perhaps you can make a case for allowing it on the NHS after all.
What do you think? Let me know via the comments form below.
Adam,
If homeopathic remedies = placebo, how do you explain homeopathic 'aggrevation' i.e the initial and transient aggravation of symptoms that can occur if too high a potency of the correctly matched remedy is given ?
Before I attempt to explain homoeopathic aggravation, I'd want to see evidence that it happens any more often with homoeopathic remedies than with placebo. After all, aggravation of symptoms happens all the time, with or without homoeopathic remedies.
Any double-blind RCTs demonstrating the effect that you could cite?
Here we go again. If you look at the real evidence, instead of the swill being pushed by Pharma and their dupes and shills, no meta has ever concluded it to be placebo; don't bother quoting Shang, when their sources were finally pried out of them, they turned out to be a couple of cherry picked "clinical" (make that "cynical") studies out of hundreds that showed verum, In fact, that's all of what the anti homeopaths have to offer for their placebo hypotheses, is cynical denial of tests that prove verum. But that's not all, because what really punches a hole in the already leaking placebo lifeboat for homeopathic skepticism (there's nothing to it) are tests on non human subjects, are tests on biochemical subjects, of which there have been numerous replications in six different categories (Google Witt "The in vitro evidence for an effect of high homeopathic potencies—–A systematic review of
the literature"); studies on the effects of dilutes on plants and animals; and now half a dozen different physical tests that are showing the structural differences between dilutes and their vehicles, the explanation for which has now been offered by highly credentialed reporters in the material scineces (Google Roy, Structure of Liquid Water for an example and more refs).
A recent paper by Nobel Laureate Luc Montagnier "Electromagnetic Signals Are Produced by Aqueous Nanostructures
Derived from Bacterial DNA Sequences" has denialists waving their magic wands at it hoping to reinterpet, discredit, or make disappear. As usual, evidence for homeopathy is treated by skeptics like big foot showing up at an Amazing Meeting; most don't see or smell it because of patholgoical blinding, and those who are conronted by the monster thinnk its a man in a monkey suit, despite the wild stink.
The point is that homeopathic skepticism is on a slippery slope, with more highly respected scientists, such as NL Brian Josephson questioning the rubber stamp denials.
For a good unbiased review of the literature Google Johnson, "Where Does Homeopathy Fit in Pharmacy Practice?"
John BENNETH
Hi John
Thanks for the comments. Did you read the systematic review by Ernst that I linked to? A systematic review of systematic reviews is about as non-cherry-picked as you can get.
I did look at the abstract of the Witt paper you referenced (the full paper was behind a paywall), and I note it said "No positive result was stable enough to be reproduced by all investigators." That's the thing, you see, if these effects were real, rather than just chance or an artifact of flawed experimental design, they'd be reproducible. They're not. If you think you can show they are, get in touch with James Randi, and you could win a million dollars.
Anyway, that's not very interesting. Those of us who have read the literature critically know that homoeopathy is just a placebo. If you want to believe it isn't, you have every right to do so, just as you have every right to believe in the deity of your choice, but be aware you will not convince the wider world unless you can come up with reproducible evidence.
What is interesting is why there are no homoeopaths making the argument for homoeopathy on the basis that placebos are effective, and that prescribing homoeopathy offers a possible way round the ethical problem of prescribing placebos, as I suggested in my original post.
If I were in favour of homoeopathy, I would be shouting that argument from the rooftops, as it's the only argument in favour of it that has some merit. Do you know why no homoeopaths seem to be taking it up?