Incidence and characteristics of the nocebo response from meta-analyses of the placebo arms of clinical trials of olanzapine for bipolar disorder

Abstract

Objectives: In the clinical setting, the nocebo phenomenon is where clinical worsening or adverse events occur as a response to a treatment, in a situation in which conditioning from previous treatment exposure and/or expectations of sickness or symptoms lead to sickness and symptoms in a conditioned or expectant individual. The nocebo response may thus be a confounder in clinical treatment and clinical research. There is a need to know how to predict if an individual is likely to be a nocebo responder, and how significant and commonplace the nocebo effect might be. Methods: An analysis was conducted on nine placebo-controlled, randomized clinical trials of olanzapine for the treatment of bi..