Pain: Placebo Effects

The placebo effect is the reduction or the disappearance of a symptom when an inert treatment (the placebo) is administered to a subject who is told, and indeed believes and expects, that it is an effective therapy. Most of the knowledge about its mechanisms comes from the field of pain, thus placebo analgesia is currently the most investigated model. However, other systems and apparatuses, such as the motor, immune, and endocrine systems, are emerging as interesting models. Although the placebo effect has so far been considered a nuisance in clinical research when a new treatment has to be tested, it has now become a target of scientific investigation to better understand the physiological and neurobiological mechanisms that link a complex mental activity to different functions ...