The Placebo Effect is when a form of therapy creates a beneficial response in a patient. While the Nocebo Effect is when a form of therapy creates a harmful effect on a patient.
Both of these phenomena are based on psychological responses rather than on a biologically active component. In other words, these reactions result from a person’s expectations, perceptions and beliefs.
This phenomena exists because the human body is essentially a biochemical pharmacy capable of releasing a variety of chemicals into the bloodstream, cells and organs that can lead to healing as well as disease. And of course these chemicals are released in the brain based on a person’s thoughts, expectations, perceptions and beliefs.