Tet

Tet
Showing posts with label traditional medicine. Show all posts
Showing posts with label traditional medicine. Show all posts

Friday, 2 August 2013

Simple Test for the Efficacy of Homeopathy

Take the "Tetenterre Challenge"

  • Homeopaths claim that their so-called "remedies" are effective. 
  • By definition, something that is effective has an effect. 
  • If something has an effect, that effect can be observed.

This offers a simple double-blind, randomised test for the claims homeopaths make:
  1. An experienced homeopath selects sufficient quantities for a dozen provings of two remedies whose provings show them to have very different, preferably opposite, effects.
  2. This homeopath selects eleven homeopath collaborators.
  3. A researcher, using techniques determined by the homeopath, distributes the pillules of each remedy into a dozen separate identical new vials.
  4. A placebo (physically identical "inert" pillules) are distributed into another dozen identical new vials.
  5. The vials are individually randomly labelled by the researcher with identification numbers.
  6. The researcher records, for each ID number, whether it holds Remedy #1, Remedy #2, or Placebo.
  7. The vials are randomly grouped into threes, each group containing one vial each of Remedy #1, Remedy #2, Placebo.
  8. The homeopath collects a package containing the vials (no contact with the researcher).
  9. The homeopath distributes the groups of vials to his/her homeopath collaborators.
  10. Each homeopath, conducts "provings" of the contents of each vial.
  11. The homeopaths use the results of the provings to identify which vials hold the placebo and which vials hold which of the two known remedies.
  12. The homeopath's identifications are compared with the researcher's records.

Any takers?

(Yes, I know that there are more holes in this than in a decent roquefort, but if homeopaths can't distinguish between "remedies" with this....)

Wednesday, 19 June 2013

Freedom of Choice and Pseudomedicine

As the demand for evidence-based medicine gathers grows, especially in the NHS where many so-called Complementary and Alternative Medicines (CAM) are being re-examined for efficacy, the CAM proponents are increasingly declaring that their particular "health modalities" should be available on the NHS as a matter of "freedom of medical choice". It is reasonable to ask what the implications of this are.

Freedom of choice is a laudable thing, provided that it is informed and responsible. Choosing something about which we know nothing is potentially as stupid as choosing to walk across a motorway -- and it can have similar consequences. The tragic example of Penelope Dingle is a case in point, but she is only the tip of a huge iceberg of harm caused directly or indirectly by pseudomedicine. As in Ms Dingle's case, she was not directly killed by homeopathy (clearly, that which has no pharmacological effect can, by definition, have no adverse pharmacological effect), but because reliance on ineffectual pseudomedicine caused her to reject conventional interventions that would have prolonged her life and which may have cured her.


I should be clear that I am not claiming that conventional medicine never gets it wrong or that it is squeaky-clean in its methodology. It isn't; there have been some appalling errors and frauds. However, using that as a reason to use something of unknown or unproven efficacy is about as illogical as using a fatal motorway pile-up as a reason to leave the car at home and choose to skate-board in the middle lane instead! The blogger Guy Chapman puts it rather more eloquently: "Problems with medicine validate homeopathy in precisely the same way that plane crashes validate magic carpets."

Making an uninformed choice for yourself is one thing. It is another to make such a choice for those for whose health you bear responsibility. Parents who, for example, make an uninformed -- or, as in the case of MMR vaccine refusal, misinformed -- choice are unwittingly putting the health of their children at risk. This is one reason that it behoves the sceptic community to contest unevidenced claims for pseudomedicine, wherever they occur.

The beneficial claims made for a number of pseudomedical practices effectively boil down to an "argument from tradition", i.e. that they have been used for centuries or millennia. Apart from the inherent illogic of this (as David Colquhoun says of herbal medicine, it is "giving patients an unknown dose of an ill-defined drug, of unknown effectiveness and unknown safety") there is also the question of harm to those species whose body parts are used for pseudomedical practices. The "traditional medicine"-induced demise of the Amur tiger and poaching of rhinoceroses for their horns are both well known and well documented, but this is merely the tip of another iceberg. According to the Smithsonian, other animals that are endangered because their body-parts are used in traditional medicine include water buffalo, the Chinese alligator, the Asian elephant, musk deer, the sun bear, Grevy's zebra, wild banteng, and the hawksbill sea turtle. This is by no means a comprehensive list of animal species that are killed or maimed in order to meet a selfish demand for "freedom of choice in medical modalities".

Some may object that the use of animals for testing conventional medicines is equally cruel. That is a matter of opinion and individual judgement (and a tu quoque fallacy to boot), but the two things are not equivalent. The one is experimenting animals to establish whether there is robust evidence of efficacy for pharmaceutical substances for whose efficacy there is already some evidence. The other is killing and maiming animals to satisfy a demand for a product for whose efficacy there is no robust evidence.

As I write this, it is "Homeopathy Awareness Week", so where does homeopathy fit into this? According to the principles of homeopathy, "Medicines derived from the animal kingdom act energetically and rapidly" and "are especially indicated in potentially fatal crises or acute disorders as well as chronic diseases that have the character of the rapid destruction of organic tissue". Amongst the animals used by homeopaths are the medusae (e.g. jellyfish), various arthropods (insects, arachnids, etc.), and numerous reptiles, including snakes and lizards. There is a recent interest in the use of body-parts of birds, including those of humming birds, ospreys, herring gulls, pea-fowl and protected (in the UK) species such as the peregrine falcon and the golden eagle. Various mammals (or their body parts or secretions thereof) are also included in the homeopathic repertory, including bottlenose dolphin, badgers, beavers, cats, cattle, sheep, musk-deer, horses and skunks. And "testicular extracts of man" (i.e. semen to the rest of us. Please don't ask.).


Whilst we are on the subject of homeopathy awareness, any gay readers might be interested to know that, according to the principles of homeopathy as elucidated by James Tyler Kent, they suffer from "a sexual perversion caused by the miasms" . You would be forgiven for thinking that this is an archaic view that is no longer held in the 21st Century. You would be wrong.

Lastly, on this topic, I would not want to leave you with the false impression that homeopaths all exploit the animal kingdom for their remedies. This is simply not the case. In this Homeopathy Awareness Week it is my duty to give fair balance by ensuring that you are aware that they also use such diverse non-animal things as bacteria that don't actually exist, the light of the planet Venus or the star Polaris, various colours, a thunderstorm, the Berlin Wall, and water (which is dissolved in ethanol and - wait for it - water!). They have even outdone ordinary physics and managed to isolate a magnetic monopole for this gem.

So, please be aware and make informed decisions on your "choice of health-care modalities".

Monday, 17 December 2012

Coins, Astrology, Pseudomedicine and Gun Control

You can try this at home!

I have just tossed a coin ten times. I got three heads and seven tails. Should I assume that this coin has a probability of 0.7 for tails and 0.3 for heads? Let's see.

That sample of ten times was one of a hundred such samples that I recorded when tossing the same coin 1000 times. Taken as a whole, I had 503 heads and 497 tails, giving a probability (to two significant figures) of 0.50 for each possible outcome. What should I assume now? That the other 900 trials were flawed, or that my penny has a statistically equal probability of heads or tails?

I suggest that reasonable people will assume that the cherry-picked ten times was a normal statistical "blip" and that the coin is, in fact, "fair".

Apologists for pseudomedicine, which include the present Secretary of State for Health, eschew the same reasoning when it comes to clinical trials. They focus on the equivalent of the trial that gave seven tails and proclaim that "some trials show that homoeopathy [or antidepressants, or some other pseudomedicine] works better than placebo".  Somehow they refuse to acknowledge that it is the totality of trials -- the thousand coin-tosses -- that must be taken into account, not just the few subsets that show a balance in favour of their pet species of pseudomedicine.

Similarly, those who subscribe to belief systems like astrology systematically ignore the many trials that demonstrate that, as a predictive or descriptive tool, it is no better than random chance and, instead, focus on those whose statistical-blip outcomes favoured the belief system.

So why do  so many otherwise intelligent people seem reluctant to apply the same reasoning to beliefs like astrology or the efficacy of pseudomedicine as they effortlessly do to coins?

The short answer is confirmation bias, probably reinforced by backfire effect. The unfortunate consequence is that those of us who are open to rational argument are unlikely to ever be able to convince those that are not.

Unfortunately, this also feeds into things like arguments for gun control, so it is unlikely that the recent appalling events in Connecticut will do anything other than polarise opinion even further.

And, following this argument to its rational conclusion, why did I even bother even to write this blog post?

I would be delighted to be shown to be wrong.