There was amazement all round when it was clinically proven that the effect of the most commonly used antidepressant was not significantly better than that of a placebo. But strangely enough, no one admires the effectiveness of the placebo. A placebo effect is any and all effects of a pill not caused by its specific chemical composition. For example, a red, yellow or orange pill is associated with a stimulating effect, while blue and green pills are thought to be calming.

A placebo can also have adverse effects. It can make a person nauseous or give them stomachache. People even get addicted to it, and develop withdrawal symptoms when the placebo treatment is terminated. There is thus sufficient reason to be interested in the effectiveness and the neurobiological mechanism of action of placebos. Lees verder »