Placebo mechanisms and reward circuitry: clues from Parkinson's disease.
Recent evidence indicates that the placebo effect in Parkinson's disease is mediated by the release of dopamine in the dorsal striatum. Interestingly, there is also placebo-induced dopamine release in the ventral striatum, which establishes a connection between the placebo effect and reward mechanisms. Specifically, we propose that placebo responses are related to the activation of the reward circuitry. Here, the clinical benefit induced by placebos represents the reward. The magnitude of the placebo effect likely depends on the a priori probability of clinical benefit. This notion has profound implications in the design of clinical trials and placebo investigations.
de la Fuente-Fernández
Raúl
R
Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.
Schulzer
Michael
M
Stoessl
A Jon
AJ
D000818:Animals; D001479:Basal Ganglia / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D006801:Humans; D010300:Parkinson Disease / Q000378:metabolism* / Q000523:psychology; D015990:Placebo Effect; D010919:Placebos / Q000494:pharmacology*; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012107:Research Design; D012201:Reward
D010919:Placebos; D004298:Dopamine