Placebo effect, not placebo treatment

In the course of reading the comments in the last several posts, I’ve come upon many mentions of the “placebo effect”. Steve Novella has a few good posts on the placebo effect, but I’d like to take a look at the clinical view.

The placebo effect is a phenomenon often observed in clinical studies. When doing clinical studies, there is often a notable change in subjects response simply by being in the study. This effect is multifactorial, often due to such biases as a desire to please researches, better medical follow up, and others. It is most often a data artifact that arises when studying human subjects.

It may seem, based on certain misunderstandings of placebo, that it would make a nice therapeutic intervention. After all, placebos are, by definition, inert and therefore harmless, so any benefit derived is essentially without risk. But placebo (by definition) not real medicine.

First, what treatment will be used as a placebo? Sugar pills? Homeopathic potions? Acupunture? There are big differences in cost, and some studies show that treatments that cost more work “better”. Is that a good thing?

Second, the placebo “effect” isn’t a real, measurable, reliable effect. There is no way to predict who will benefit or to what degree. Prescribing a placebo is a bit like saying, “Try hard to feel better. If it works, I let my sugar pill take the credit.” Unlike proven interventions, there is no predictable dose, response, or benefit.

There is also an ethical problem with some placebos. Some of the placebo effect arises simply from being cared for (as is seen in many clinical studies), but a few placebo treatments require actively deceiving a patient. For example, if you tell a patient, “Hey, I’m going to give you this homeopathic treatment. It doesn’t really do anything, but maybe you’ll get lucky,”—if you tell a patient that, it is a reasonable guess that some of the placebo effect may be mitigated by sketicism.

As has been pointed out by others, even were a placebo to be somewhat predictable, there is only a limited number of symptoms that might even be amenable. For example, it’s reasonable to posit that some pain relief might be gained from placebos, as pain has a large subjective component. But you won’t see placebos curing cancer, aborting a heart attack, or lowering blood sugar.

Placebo is an interesting phenomenon, but is not a clinical tool. It’s appearance is serrendipitous, and its use unethical.