Placebo effects are beneficial effects that are attributable to the brain–mind
responses to the context in which a treatment is delivered rather than to the specific
actions of the drug. They are mediated by diverse processes — including learning,
expectations and social cognition — and can influence various clinical and physiological
outcomes related to health. Emerging neuroscience evidence implicates multiple brain
systems and neurochemical mediators, including opioids and dopamine. We present an
empirical review of the brain systems that are involved in placebo effects, focusing on
placebo analgesia, and a conceptual framework linking these findings to the mind–brain
processes that mediate them. This framework suggests that the neuropsychological
processes that mediate placebo effects may be crucial for a wide array of therapeutic
approaches, including many drugs.