“I know that this treatment works on me, I don’t need scientific studies to demonstrate its effectiveness.” Anyone who upholds the principles of evidence-based medicine hears this phrase with unfailing regularity. Whether you’re talking about homeopathy, osteopathy, energy healing, Bach flowers or any other questionable treatment, and however much solid scientific evidence you present to the alternative medicine friend who gives you this speech, this one – yes, in France as in most other countries, it is usually a woman – will just shrug his shoulders with a condescending smile and say, “Don’t be silly, I know it works, because I tried it myself, and it helped!”
This type of argument is as common as it is difficult to refute. Any attempt to doubt automatically gives the impression that you imply that your friend is lying. Yet she knows tell the truth: after all, she tried her favorite therapy and it worked. You and your friend are saying seemingly opposite things – but, in a way, you’re both right. Her treatment – suppose she used a remedy based on Bach flowers – is not effective; to be sure, you can even rely on a systematic review that I published myself. Yet your friend isn’t lying, because she actually felt better after using it. This contradiction illustrates the tension between scientific evidence and personal experience.
“Experience can be deceiving”
Scientific evidence can be simple. In the case of Bach flowers, we know that the vials do not contain enough active ingredients to have health effects. We also know that the treatment is implausible. Finally, we know that the available clinical trials have not demonstrated efficacy. The situation is therefore quite clear – and it is understandable that as an advocate of evidence-based medicine you remain adamant about your position.
Your friend, however, is equally adamant. She has felt the benefits of her Bach flower treatment and is therefore totally convinced that your evidence is wrong. She feels she knows her body well enough to be able to tell the truth and may even be upset by your doubts about her experience. What she doesn’t understand, however, is how misleading her experience can be.
If experience were a reliable indicator of a therapy’s effectiveness, we wouldn’t need expensive science or clinical trials. It would suffice to ask patients about their experience. In fact, this is pretty much the situation in which medicine found itself two hundred years ago. And that’s why, two centuries back, people died like flies as soon as they were struck down with disease. Fortunately, we have evolved and learned not to rely on experience but on evidence to decide the true value of a treatment.
Placebo effect, spontaneous remission…
Today we understand that your friend’s experience may seem simple, but it is actually quite a complex phenomenon. It is determined not only by the effect of the therapy, in this case the Bach flowers, but also by a number of other factors. For example, your friend paid dearly for her treatment, so she had high expectations. In other words, she may have benefited from a significant placebo effect. Also, his symptom (e.g., pain) might have gone away on its own. This spontaneous remission would have given him the impression that these treatments were effective. And, of course, your friend could have taken paracetamol to treat her pain and then forgotten about it thinking that the Bach flowers had done the trick.
As I said, the experience of purported therapeutic benefit is based on multiple factors and therefore can be misinterpreted. As humans, we are wired to see cause and effect relationships where none exist. Whenever a dramatic event occurs, we tend to look for the cause. The symptom relief is undeniably dramatic and we automatically seek an explanation. So your friend should be excused for emphatically claiming that the Bach flowers are the cause of her pain relief. The truth is more complex and therefore less likely to come to mind.
This is all well documented and completely logical. But it’s far from easy to explain to someone who’s had a positive experience with a bogus treatment. Every time I hear someone say, “Don’t be silly, I know it works, because I tried it myself, and it helped!” I say, “And without your fake treatment, your symptom would have disappeared even faster.”
However, I must warn you that these types of responses can turn out to be a quick method of losing friends.
* Edzard Ernst is Emeritus Professor at the University of Exeter, UK, where he specialized in the evaluation of alternative medicine. He is the author of numerous books, including Don’t Believe What You Think: Arguments for and against SCAM (Societas, 2020), SCAM: So-Called Alternative Medicine (Societas, 2018).