The nocebo effect in current practice
In 2013, the European Journal of Neurology published a meta-analysis examining patient dropout rates owing to medication side effects in clinical trials for Parkinson disease treatments.1 A review of more than a decade of various trials showed that nearly two-thirds of patients reported an adverse event after drug therapy. Worse still, nearly one-tenth (8.8%) of the patients in a specific arm of the studies experienced such horrific side effects that they were forced to stop treatment altogether. Strangely, this subset of patients had not been given any active medication at all—they had been given a placebo.
The placebo arm of a research study is crucial to the modern scientific method and is used to better understand the medication and confirm that it gives a true result beyond subjective experience. Much has been written about the placebo effect in recent years, but lesser known and understood is placebo’s evil twin, the nocebo.
a harmless substance or treatment that when taken by or administered to a patient is associated with harmful side effects or worsening of symptoms due to negative expectations or the psychological condition of the patient.2
