Words can Heal, Words can Kill: Understanding the Mechanisms through Placebo and Nocebo Research
Although placebos have long been considered a nuisance in clinical research, today they represent an excellent model to understand how words and therapeutic rituals may affect the patient’s brain. Placebo effects, and their evil twins, nocebo effects, are today an active and productive field of research and, because of the involvement of many mechanisms, the study of the placebo effect can actually be viewed as a melting pot of concepts and ideas for neuroscience. Indeed, there exists not a single but many placebo effects, with different mechanisms and in different systems, medical conditions, and therapeutic interventions. For example, brain mechanisms of expectation, anxiety, and reward are all involved, as well as a variety of learning phenomena, such as Pavlovian conditioning, cognitive and social learning. There is also some experimental evidence of different genetic variants in placebo responsiveness. Overall, placebo and nocebo effects are triggered, respectively, by positive and negative verbal suggestions, thus emphasizing how positive and negative words can have powerful effects on the course of illnesses and symptoms. Therefore, today we can talk of a true pharmacology and toxicology of words, whereby the unique and special interaction between the therapist and his/her patient can activate the same mechanisms that are the target of drugs.
University of Turin Medical School and Hypoxia Medicine School, Italy/Switzerland