Friday, July 20, 2007

Placebo effect: There is no such thing

placebo pill
Part 1/3

Placebo, those sugar pills without any drug, are widely used in medical studies in order to rule out the so-called placebo effect. In earlier posts I have mentioned placebo, sometimes in the meaning of a useless treatment, and I am going to use it in many more posts to come. Thus, it's high time to go a bit deeper into what is really behind a placebo. In the first post of my three-part series I deal with the fact that the placebo effect is not an effect of placebo but of mind.

Is skepticism a placebo killer?

After having posted about valerian being useless as a sleep aid, I have asked myself about possible unwanted outcomes: For instance, a valerian user reads my post, loses his belief, switches to a powerful tranquilizer, gets addicted and many years later his kidneys are destroyed. Of course this looks like ethical over-concern of a blogger who overrates his influence, but it may contain a grain of truth. Anyway, these have been the ideas that have pushed me to this series about placebo effect.

Back to reality. If someone takes valerian or Bach flower remedies and feels better, he may read negative reports, shrug his shoulders and say to himself I know better.

Even more important: The truth cannot be a placebo killer as far as we have got the point that the real cause of the placebo effect is not in the placebo.

Why there is no effect in placebo

As we all know there is no active substance in a placebo. Hence, simple logic tells us that a placebo as such cannot have any effect. If there is an effect, it is triggered by taking the placebo, but it is not caused by the placebo. Several theories have been set up in order to explain this effect.

The most simple theory (spontaneous remission) assumes that the patient would have improved anyway, without any treatment. In a strict sense, this is not an explanation of the placebo effect but an alternative scenario that should be ruled out before we speak of a placebo effect.

Another theory (autosuggestion) assumes that the patient feels better just because he expects to feel better, but that the objective conditions in his body remain unchanged.

A third group of theories (psychosomatics) assumes that mind, triggered by taking the placebo, has a positive influence on the self-healing forces of the body, either by conditioning or motivation.

Take home message
Taking placebo may have an effect but this is a mind effect. The second post of this series deals with the question of how to make best use of it.

Photo credit: Wellcome Library, London

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