Neural correlates of placebo effect: Review and future implications

Abstract

Experimental and clinical research has documented expectancy related symptom improvement in a variety of conditions, leading to a growing interest in the placebo effect. Despite significant treatment outcomes, placebo-induced effects have been regarded as nonspecific psychological factors associated with the subjective experience of healing that operates different than the actual drug agent . However, neuroimaging research revealed more complex regulation of the placebo response, which indicates a top-down regulation of the symptom improvement enhanced by the expectancy effects. It appears that, placebo response is not solely function of higher order control processes, but also involves diverse disease-specific neurobiological mechanisms. In the current review, neural mechanisms underlying placebo effect have been addressed focusing on the analgesia, Parkinson’s disease and major depression. Along with the opiate system, dopaminergic and serotonergic functions in the brain are discussed in relation with the three target conditions. Last, potential implications of the placebo research are discussed with respect to experimental and clinical practice.