Neurobiological and neurochemical mechanisms of placebo analgesia

Abstract

Background: The efficacy of pain therapies can be substantially modulated by treatment expectations, which is reflected by the substantial placebo effects observed in pain (so called placebo analgesia). Question: What is currently known about the neurobiological and neurochemical mechanisms underlying placebo analgesia? Materials and methods: A focused presentation of key publications in the field embedded in a structured overview of the mechanistic concepts and current theories according to recent evidence. Results: Experimental studies with functional neuroimaging showed that the effect of placebo analgesia is reflected by changes in brain activity related to pain processing and cognitive control. The important neurotransmitters involved include opioids and dopamine. Conclusion: Placebo analgesia is associated with complex neurobiological and -physiological mechanisms. An advanced comprehension of these processes should be applied to optimize existing and future therapeutic approaches in pain therapy.