Nonspecific Medication Side Effects and the Nocebo Phenomenon

Patients taking active medications frequently experience adverse, nonspecific side effects that are not a direct result of the specific pharmacological action of the drug. Although this phenomenon is common, distressing, and costly, it is rarely studied and poorly understood. The nocebo phenomenon, in which placebos produce adverse side effects, offers some insight into nonspecific side effect reporting. We performed a focused review of the literature, which identified several factors that appear to be associated with the nocebo phenomenon and/or reporting of nonspecific side effects while taking active medication: the patient's expectations of adverse effects at the outset of treatment; a process of…