Placebo and Nocebo Effects

Although historically viewed as the outcomes of inert treatments, placebo and nocebo effects represent the component of medical treatment effects resulting from psychological factors. Researchers have found evidence for placebo and nocebo effects in both classic and contemporary medicine. Randomized controlled trials (RCTs) are required to account for this effect in medical research. Experimental evidence indicates that placebo and nocebo effects are caused by expectations and conditioning. Although reliable personality differences have rarely been found, situational factors frequently alter the magnitude of placebo effects. Modern research is uncovering the neurobiological processes responsible for placebo effects, particularly with placebo analgesia. Work on placebo and nocebo effects bridges disciplines and points to new avenues for improving patient care and increasing our understanding of the interplay of mind and brain processes.