Thursday, 20 December 2007

Muddying the water: Rustum Roy in the Grauniad

For me, Christmas came early this year, in the shape of a Guardian ‘Response’ piece by Rustum Roy, of all people. Roy is an eminent professor of materials science at Pennsylvania State University, but he also appears periodically to try and give scientific justification for homeopathy. I’m sure others will write about this, but I feel vaguely involved because of Roy’s connections to the recent ‘memory of water’ fiasco in the journal Homeopathy. Roy’s piece is entitled ‘“Homeophobia’ must not be tolerated”, and it seeks to rebut Ben Goldacre’s excellent and celebrated piece on homeopathy that was published in the Guardian’s G2 supplement a little while ago. There’s a lot of drivel for such a short piece, but I’ll try to keep it concise.

Roy begins by stating “For the record, I have never studied or held a position for, or against, the clinical effectiveness of homeopathy”. This seems a strange statement, given that Roy is responding to Ben Goldacre’s piece which mainly discussed that clinical evidence. Avoiding discussion of clinical evidence allows Roy to erect a classic straw man. He suggests that scientists main objection to homeopathy is the very high dilutions, such that there is very little chance of any of the original substance remaining, that are routinely used in homeopathic remedies. Indeed, many scientists do quite reasonably object to this, but the main objection to homeopathy is simply that the clinical evidence shows that it doesn’t work.

Unfortunately, Roy is not on firmer ground when discussing his own field of materials science. He attempts to create a theoretical justification for homeopathy, based on the idea of water being able to structurally ‘remember’ substances that are no longer present. Roy states that it is the structure of water that is important, not what it contains, and references Prof Eugene Stanley of Boston University in saying that there must be at least 64 different structures that occur in liquid water. He compares this to graphite and diamond, which are chemically of the same composition but have radically different properties because they have radically different structures. In this way he seeks to get around the problem of homeopathic remedies typically being diluted so much that it is very unlikely that any of the original substance can possibly remain. It’s the structure of the water that has an effect, not the substances dissolved or suspended in the water.

The fact that water can have so many different structures is interesting, but in terms of homeopathy it doesn’t really get us any further forward. To demonstrate even a theoretical justification for homeopathy, Roy would still need to show that the hundreds of different homeopathic remedies could all create different structures in water; that only the specific remedy, and not any other impurities in the water, causes this structuring; that water with different structures has different biological effects, and that the strength of that effect could increase as a solution is further diluted. So far Roy has only shown that water can contain interesting structures. One thing you could do to test Roy’s hypothesis is try to distinguish homeopathic remedies on the basis of structural differences between them. In fact, Roy and co-workers claim to have done this using spectrophotometric techniques, in a paper recently published in Homeopathy. This paper is so flawed that it’s almost a shame Roy doesn’t mention it in his piece. It doesn’t contain any usable observations, and all it shows is that the alcohol used to prepare the tested remedies likely came from multiple sources.

Roy also states that Prof Martin Chaplin of South Bank University has, in the journal Homeopathy, “discussed how water could retain a ‘memory’”. In fact, Chaplin has done no such thing. He has simply demonstrated that water has a lot of unique and interesting properties, something which is not in dispute. He doesn’t show how the structure of water in a homeopathic remedy could be influenced by substances that are no longer present. I will have a critical letter to the editor of Homeopathy published shortly outlining this point in more detail.

Roy says that the placebo effect is ‘without doubt present in every homeopathic intervention’, but goes on to say that ‘it is far more powerfully present in orthodox medical pills because they are advertised so widely in billion-dollar campaigns’. I’m not aware of any evidence that this is the case, although I’m certainly not an expert in this field. It seems unlikely because orthodox medicines are usually trialled for efficacy and safety before they come on the market. But in any case it seems like a confused argument. If the placebo effect ‘works’ and it is more powerful in ‘orthodox medical pills’, isn’t this evidence that orthodox medical pills are better? The central point is that the clinical evidence shows that homeopathic remedies have no more benefit than a sugar pill, while orthodox medicines do. But Roy conveniently doesn’t take a position on the clinical evidence.

Roy closes by asking whether Goldacre ‘seriously believes that a homeopathy paper with a positive outcome would be treated fairly in any mainstream journal’. In fact, a number of such papers have been published, although they have generally turned out to be flawed. One example is a paper on homeopathic treatment of critically ill patients that appeared in Chest, and has been thoroughly trashed here. The problem is not with the bias in mainstream journals, it is with the quality of research into homeopathy. Hence the Shang et al. meta-analysis found only 165 trials of homeopathy that matched the inclusion criteria, compared to 353,809 conventional trials. Trials of homeopathy are usually published in specialised journals whose standards of scrutineering leave a lot to be desired.

Essentially, Roy has failed to show that what he calls ‘homeophobia’ is anything other than a sensible response to the evidence that homeopathy doesn’t work, especially given that homeopaths are giving irresponsible and dangerous advice about such things as malaria.

5 comments:

apgaylard said...

Excellent points. Shame that such a bright man publishes an article in a national newspaper containing so many weak and irrelevant points.

What are the odds dullman will turn up telling you that you can't criticise a man with so many Nature 'articles'?

Paul Wilson said...

It really was an astoundingly poor article, wasn't it?

It wouldn't be too much of a surprise for Ullman to show up. Bring it on, I say.

Mojo said...

With regard to Roy's comment about "orthodox medical pills" having a more powerful placebo effect than homoeopathy:

The placebo effect is a result of the patient's belief that a treatment is effective. It is certainly going to apply at least as much to real medicine as to homoeopathy. In the case of medicines that have real effects, if the patient has previously observed the effects themselves, they will certainly have a powerful reason for believing in them - perhaps a more powerful reason than would be possible in the case of a "medicine" that has no real effects. So perhaps it could be argued that genuinely effective treatments might produce a more powerful placebo effect than ineffective ones.

It's a little difficult to see what Roy's point is, though. In trials of new medicines, the subjects will presumably not have encountered the particular treatment before, and in any case properly controlled and blinded trials will eliminate the placebo effect from the results.

It looks as if he's putting up another strawman: suggesting that people argue that homoeopathy doesn't work because it produces a placebo effect, and implying that this isn't a valid argument because, by the same argument, he could say that real medicines don't work either because they also produce a placebo effect. But, of course, he's addressing an argument that nobody has made. In fact, people argue that homoeopathy doesn't work because it has no effect over that of placebo, not simply because it produces a placebo effect.

Paul Wilson said...

Yes, it's certainly difficult to understand what Roy's point is. In fact, that seems to be a problem with the whole article. It reads as though it was put together very quickly, perhaps close to a deadline, and as an article it doesn't really have any coherent thread or shape.

Paul Wilson said...

Via the Bad Science forum, I came across a letter to Current Oncology by Lionel Milgrom, talking about 'memory of water'. There is a response from a Dr. Stephen Sagar, who writes 'Unfortunately, material science data is being fitted retrospectively to a paradigm of homeopathy that has not been proven to result in clinical effects (over and above placebo) in the real world'. This is such an accurate summary of what is going on with 'memory of water' that I wish I had thought to put it that way myself.