Tuesday, May 24, 2011

The power of faith

Here's an interesting article in The Economist about the placebo effect in medicine:
A placebo is a sham medical treatment—a pharmacologically inert sugar pill, perhaps, or a piece of pretend surgery. Its main scientific use at the moment is in clinical trials as a baseline for comparison with another treatment. But just because the medicine is not real does not mean it doesn’t work. That is precisely the point of using it in trials: researchers have known for years that comparing treatment against no treatment at all will give a misleading result. ...

One conclusion emerging from the research, says Irving Kirsch, a professor at Harvard Medical School who wrote the preface to the volume, is that the effect is strongest for those disorders that are predominantly mental and subjective... In the case of depression, says Dr Kirsch, giving patients placebo pills can produce very nearly the same effect as dosing them with the latest antidepressant medicines.

Pain is another nerve-related symptom susceptible to treatment by placebo. Here, patients’ expectations influence the potency of the effect. Telling someone that you are giving him morphine provides more pain relief than saying you are dosing him with aspirin—even when both pills actually contain nothing more than sugar. Neuro-imaging shows that this deception stimulates the production of naturally occurring painkilling chemicals in the brain. A paper in Philosophical Transactions by Karin Meissner of Ludwig-Maximilians University in Munich concludes that placebo treatments are also able to affect the autonomic nervous system, which controls unconscious functions such as heartbeat, blood pressure, digestion and the like. Drama is important, too. Placebo injections are more effective than placebo pills, and neither is as potent as sham surgery. And the more positive a doctor is when telling a patient about the placebo he is prescribing, the more likely it is to do that patient good.

Drama is important, and so is a positive attitude. This really is faith-based medicine. Witch-doctors always were dramatic and always certain of their procedures (or, at least, expressed such certainty to their patients). And so are complementary and alternative medicine practitioners these days.
Unlike their conventional counterparts, practitioners of alternative medicine often excel at harnessing the placebo effect, says Dr [Edzard] Ernst [professor of complimentary medicine at the Peninsula Medical School in England]. They offer long, relaxed consultations with their customers (exactly the sort of “good bedside manner” that harried modern doctors struggle to provide). And they believe passionately in their treatments, which are often delivered with great and reassuring ceremony. That alone can be enough to do good, even though the magnets, crystals and ultra-dilute solutions applied to the patients are, by themselves, completely useless.

I understand why people go to quacks, rather than to real doctors. A visit to the doctor can be frustrating. (In my experience, it's almost always frustrating.) Most doctors don't seem to listen, and usually don't even seem to care. If they can't help, they just shrug it off. After all, they've got more important things to do (but probably not more important to you).

Alternative medicine practitioners probably can't help, either, but they think they can. Or, at least, they say they can. And they act like they care. Their treatments might be complete nonsense, but if you think they'll work, they might - especially on very subjective matters, such as pain relief.

But, of course, there are definite limitations to placebos. The point of medicine - real medicine - is to do better than placebos. That's why real medicine is tested against controls. And we've made huge progress. Medical care these days is far better than what a witch-doctor or other faith-healer could have done for us centuries ago, and far better than what faith-healers can do for us today.

Most alternative medicine is a scam. Promoters might believe in what they're pushing or might not. (Most likely, alternative medicine practitioners do believe in what they're doing, because it's always easy to believe what you want to believe.) The industry is big money these days, but their supporters also have faith. Well, faith is a terrible thing, especially when it's misplaced.
Over the years Dr Ernst and his group have run clinical trials and published over 160 meta-analyses of other studies. (Meta-analysis is a statistical technique for extracting information from lots of small trials that are not, by themselves, statistically reliable.) His findings are stark. According to his “Guide to Complementary and Alternative Medicine”, around 95% of the treatments he and his colleagues examined—in fields as diverse as acupuncture, herbal medicine, homeopathy and reflexology—are statistically indistinguishable from placebo treatments. In only 5% of cases was there either a clear benefit above and beyond a placebo (there is, for instance, evidence suggesting that St John’s Wort, a herbal remedy, can help with mild depression), or even just a hint that something interesting was happening to suggest that further research might be warranted.

It was, at times, a lonely experience. Money was hard to come by. Practitioners of alternative medicine became increasingly reluctant to co-operate as the negative results piled up (a row in 2005 with an alternative-medicine lobby group founded by Prince Charles did not help), while traditional medical-research bodies saw investigations into things like Ayurvedic healing as a waste of time.

Yet Dr Ernst believes his work helps address a serious public-health problem. He points out that conventional medicines must be shown to be both safe and efficacious before they can be licensed for sale. That is rarely true of alternative treatments, which rely on a mixture of appeals to tradition and to the “natural” wholesomeness of their products to reassure consumers. That explains why, for instance, some homeopaths can market treatments for malaria, despite a lack of evidence to suggest that such treatments work, or why some chiropractors can claim to cure infertility.

Think about it. 95% of such treatments were shown to be ineffective, and of the other 5%, there might only be "a hint that something interesting was happening." That's a far cry from actually being an effective treatment.

There are at least three things to take from this:

First, real medicine has to demonstrate, under strict controls, that it actually works - and works better than a placebo. I don't care how much money the pharmaceutical industry has - and yes, money always has influence - they've still got to get through stringent scientific trials. Those trials won't always work as intended, but they're still the best way we've ever discovered at separating the wheat from the chaff.

Second, complementary and alternative medicine, and "natural" supplements and the like, generally get a free pass on showing that they actually do anything worthwhile. That's because they're popular (faith-based thinking is clearly dominant, at least here in America), and politicians will usually bend over backward for anything popular.

But that's why they can continue to sell stuff - billions of dollars worth - that has not been shown to be effective and that, indeed, has frequently been proven to be completely worthless. Except as a placebo, of course. Homeopathy, for example, has never been shown to work, but belief is a powerful thing. And, of course, there's a lot of money behind this industry, too.

And third, keep in mind that the placebo effect also works with real medicine. When you take aspirin, you get the pain reliever in aspirin along with the placebo effect of taking the pills. If you think that Aleve or Tylenol work better than aspirin, they probably will. But at least part of that will be because of the placebo effect.

I don't know which pain reliever actually works best in clinical trials, and I suspect there's some individual variation, anyway. But if you find one you think works better than the others, it probably will. That's because - partly, at least - the placebo effect will be greater with that one. Yes, the placebo effect is part of what makes real medicine effective, too.

Funny, isn't it? But always keep in mind that taking real medicine has benefits in addition to just the placebo effect. With real medicine, you do get the placebo effect, but also more than that. Personally, I don't like being scammed out of my money. And I don't like to feel gullible, in any case. So I always want to use what's been demonstrated, in careful scientific research, to actually work.

And you know? I'd like to see complementary and alternative medicine required to follow the same rules as real medicine. If you claim it works, then demonstrate that. If it really does work, you should be able to do that, right?

2 comments:

Chimeradave said...

This is certainly true. When I take tylenol I usually sit quietly have a glass of water and wait for the headache to subside. How much of it is the tylenol and how much of it is the slowing down and relaxing or even the glass of water. Who knows, but if it ain't broke I'm not fixing it, you know?

Then sometimes I take an allergy medicine Loratadine in a melt-away. I take that and I almost instantly feel my nasal passages opening up. Part of that has to be placebo effect, right?

WCG said...

I think so, John. That's what struck me about this. I've long known about the placebo effect and why people can think such foolish things about quack medicine. But this is the first time I really thought about the fact that real medicine has a placebo effect, too.

Yeah, it seems obvious now, but I just never really thought about that before.