Edzard Ernst: Thousands of patients cannot be wrong or can they?

The subject of alternative medicine (AM) is littered with surveys, and it almost seems as though a new one crops up every other day. Typically these surveys assess how many patients use AM. The resulting prevalence figures show an extremely wide range. One reason for this huge variability is that most of these surveys are so flimsy that their findings are therefore unreliable.

Nevertheless, collectively they give us a vague inkling that the prevalence of AM-use is considerable. In UK general populations, the one-year prevalence of AM-use seems to be around 20%, according to the most reliable data we have at present. In other words, thousands of UK consumers and patients employ AM, and most pay for it out of their own pocket.

“So what?” you might well ask. But proponents of AM are fascinated by such information and tend to take it several decisive steps further: AM users are obviously satisfied with the service they get—otherwise they would hardly carry on paying for it. This means that patients experience some sort of benefit from using AM. This surely must be proof that AM works.

Once we have followed this logic, AM proponents point out that this situation is grossly unfair. Why should only such people enjoy the benefits who happen to be rich enough to afford paying for AM? From here, it is only a small step to demand that AM should be available for all on the NHS.

This “argumentum ad populum” holds that anything that is accepted by lots of people must be alright. Who needs expensive clinical trials of AM when people have already voted with their feet and wallets? AM may not be supported by biological plausibility nor by clinical efficacy, but who cares? It has been “field tested” on thousands of people for hundreds of years.

This line of thinking seems so logical that many of us find it difficult to argue against it. Yet we only need to consider alternative explanations for the current popularity of AM. It could be a thing of fashion; it probably is due to clever advertising; it might be the result of the public’s gullibility; it could be the Zeitgeist (“you are worth it”) etc, etc. Popularity is not remotely the same as efficacy, fads do not constitute evidence, and common approval is no substitute for scientific proof.

If many people use, and swear by, a therapy, this might simply indicate that many people can make the same mistakes, fall for the same attractions, misunderstandings, or fabrications. In other words, the “argumentum ad populum” is a classical fallacy.

Edzard Ernst is a professor of complementary medicine at the Peninsula Medical School, Exeter.