It is becoming increasingly clear that the placebo effect has a great influence on medical treatment. An international, interdisciplinary team of researchers led by Professor of Health Psychology Andrea Evers from Leiden University has now written a first set of guidelines on how to apply the placebo effect in clinical practice. Publication in Psychotherapy and Psychosomatics.
The effect of many health-care treatments is explained in part by factors other than the medication or treatment itself, Andrea Evers explains. For instance, the doctor's confidence that the treatment will work , people's expectations of the treatment and any previous experiences they might have of a treatment. The placebo effect describes how a person's positive expectation of a treatment can have a positive effect on it. In contrast, the nocebo effect is a negative effect: for instance, if a patient experiences side-effects due to negative expectations of the medication.
'Placebo and nocebo effects influence the outcome of the treatment. We know this from scientific research,' says Evers. 'But the regular health-care system takes very little account of these findings when this knowledge would enable us to optimise treatments and at the same time reduce any adverse effects (such as side-effects).'
The publication in Psychotherapy and Psychosomatics is a first step in this direction. It was the result of the first official conference of the Society for Interdisciplinary Placebo Studies (SIPS), which was held in Leiden last year. During an interdisciplinary workshop led by Evers, a group of leading international researchers reached the consensus that knowledge about placebo and nocebo effects could lead to better treatment results with fewer side-effects. According to the researchers, it is crucial that patients receive more information about these effects, and that doctors receive training on the best doctor-patient communication to maximise placebo effects and minimise nocebo effects.
The group believes that future research should look at how to implement these recommendations in clinical practice. Evers: 'Now we have reached an international consensus on this, we can research how doctors and patients can benefit in everyday practice.'
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