Placebo and Pain Chapter 8. Positive and Negative Emotions and Placebo Analgesia

Pain may be modulated by positive and negative emotions, and this is the basic element in the hypothesis that placebo effects are due to a reduction in negative emotions. Individual differences are discussed, especially as they relate to negative emotions. There is evidence that the placebo effect is partly due to a reduction in negative emotions. The role of positive emotions in placebo analgesia is less studied, and the data are mixed. The nocebo effect, the opposite of the placebo effect, can be explained by increased negative emotions. Taken together, the placebo and nocebo effects may be seen as different consequences of changes in emotional processes.