ABSTRACT
Although placebos have long been considered a nuisance in clinical research, today they are an active and productive field of research and, because of the involvement of many mechanisms, they can actually be viewed as a melting pot of concepts and ideas for neuroscience. For example, brain mechanisms of expectation, anxiety, and reward are all involved, as well as a variety of learning phenomena such as Pavlovian conditioning and cognitive and social learning. There is also some evidence of different genetic variants in placebo responsiveness, and these give rise to high response variability. Overall, the concept that is emerging today is that placebos and drugs share common mechanisms of action. The understanding of these mechanisms in placebo responders and nonresponders has important clinical implications and applications for both pharmacological and nonpharmacological treatments, including hypnosis.
