Expectation and dopamine release: mechanism of the placebo effect in Parkinson's disease.
The power of placebos has long been recognized for improving numerous medical conditions such as Parkinson's disease (PD). Little is known, however, about the mechanism underlying the placebo effect. Using the ability of endogenous dopamine to compete for [11C]raclopride binding as measured by positron emission tomography, we provide in vivo evidence for substantial release of endogenous dopamine in the striatum of PD patients in response to placebo. Our findings indicate that the placebo effect in PD is powerful and is mediated through activation of the damaged nigrostriatal dopamine system.
de la Fuente-Fernández
R
R
Neurodegenerative Disorders Centre, TRIUMF, University of British Columbia, Vancouver, BC, Canada V6T 2B5.
Ruth
T J
TJ
Sossi
V
V
Schulzer
M
M
Calne
D B
DB
Stoessl
A J
AJ
D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001058:Apomorphine / Q000008:administration & dosage / Q000627:therapeutic use*; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000378:metabolism; D015990:Placebo Effect; D010919:Placebos / Q000008:administration & dosage; D020891:Raclopride / Q000378:metabolism; D013569:Synapses / Q000378:metabolism; D014055:Tomography, Emission-Computed
D000978:Antiparkinson Agents; D010919:Placebos; D020891:Raclopride; D001058:Apomorphine; D004298:Dopamine