Nocebo is the antipode of placebo and refers to adverse events a person manifests after receiving placebo. Recent findings: In randomized trials for migraine prevention meta-analyses revealed that eight out of 20 patients treated with placebo experienced any adverse event. More importantly, one out of 20 patients treated with placebo withdrew treatment because of adverse events. The adverse events in placebo groups mirrored the adverse events expected of the active medication studied, confirming that pretrial suggestions induce the adverse events in placebo-treated patients. Nocebo was higher in preventive treatments than in symptomatic ones.

Patients in randomized clinical trials frequently stop taking their drug, complaining of side effects. However, it turns out that some of these subjects are part of the placebo group and thus never received any active medication. This is a case of the nocebo effect seriously interfering with medical treatment. Tinnermann et al. investigated whether value information such as the price of a medication can further modulate behavioral nocebo effects and the underlying neural network dynamics (see the Perspective by Colloca). They used brain imaging to characterize the circuits involved in nocebo hyperalgesia within the descending pain pathway from the prefrontal cortex to the spinal cord.