Dwalingen in de methodologie. XVII. Het placebo-effect

- The placebo effect is well known, but there are many misconceptions.

- One of these misconceptions is that one-third of patients respond to placebos. This misunderstanding is probably due to methodologically poor research conducted in the 1950s.

- Another error is that the effect in the placebo arm of a clinical trial is often confused with the placebo effect.

- The belief in the placebo effect is enormous, but the quantity and quality of data to substantiate this belief are very limited.

- Investigating the placebo effect is methodologically difficult, not easy to get financed and considered unrewarding.