Glossary · Methodology
Nocebo
In short
Nocebo is the counterpart of placebo: symptoms that arise because people expect side effects — even under a sham treatment. The symptoms are real, but their cause is not the active ingredient.
Anyone who reads in the package leaflet that headaches or muscle aches are common pays attention to them and attributes everyday complaints to the medicine. In studies this shows up when the placebo group also reports many of the side effects.
For interpretation this means: a side effect can only be attributed to the active ingredient if it occurs more often under it than under placebo. Conversely, the nocebo effect is not imagination in a dismissive sense but a well-described phenomenon — and a common reason why effective treatments are stopped.
Expectation can cause symptoms — the comparison with placebo shows which ones.
Where this comes up in the fact checks
- Statins – In SAMSON and StatinWISE, people who had stopped statins because of complaints received statin and placebo in turn without knowing which. The complaints were almost as strong under placebo.
Sources
Related terms: Placebo · Double-blind
Information only, not medical advice. The BK-Score is a subjective assessment according to disclosed rules – not a scientific evaluation. Scoring rules