Placebo and Nocebo Effects: Biological and Cultural Aspects

Improvement or benefit in a patient treated with a placebo is a placebo response and worsening or adverse effects in a patient treated with a placebo is a nocebo response. Both placebos and nocebos are inert treatments that have no known mechanism of action for the condition being treated. Curiously, the administration of a placebo may activate the same biological pathways targeted by some verum treatments. Placebo and nocebo phenomena are not rare occurrences that result from specific conditions or characteristics of treatment. Rather, they permeate the treatment environment and moderate treatment outcomes. Outcomes can be affected by the treatment setting, the discourse between the clinician and the patient, and the actions, manner, and professionalism of the clinician, described as “the treatment ritual.” All forms of treatment involve a treatment ritual, and this ritual is believed to be the trigger of the placebo or nocebo response. The treating clinician can deploy or mitigate placebo and nocebo effects by taking into consideration the expectations and perception of the patient to enhance the benefits of treatment and minimize adverse effects.