Reward pathways in Parkinson's disease: clinical and theoretical implications.
OBJECTIVE
The mesolimbic and mesocortical circuits are particularly involved in reward-related behavior in humans. Because these systems may be in some way altered in Parkinson's disease (PD), it is likely that some psychiatric manifestations of PD, such as hedonistic homeostatic dysregulation and pathological gambling, as well as impulsive decision making, may be ascribed to their involvement. The aim of the current article was to review recent literature on this topic in order to analyze whether these disturbances share a common ground and whether actual theoretical frameworks on addiction prove a useful tool for their interpretation.


METHODS
Data were identified on searches of MEDLINE/PubMed databases from relevant articles published up until March 2007.


RESULTS
All clinical manifestations (hedonistic homeostatic dysregulation, pathological gambling and impulsive decision making) seem to share a common multifaceted ground in which factors related to antiparkinsonian therapy, premorbid personality and progression of disease interact. Theoretical interpretations and conclusions drawn from experimental studies may help to shed light on the underlying pathological mechanisms.


CONCLUSIONS
Further studies are needed to analyze why, despite a common ground, only some patients develop those neuropsychiatric complications described here.
Torta
Diana M E
DM
Department of Psychology, University of Turin, Torino, Italy. diana.torta@unito.it
Castelli
Lorys
L
D000368:Aged; D000978:Antiparkinson Agents / Q000009:adverse effects / Q000627:therapeutic use; D002540:Cerebral Cortex / Q000503:physiopathology*; D003657:Decision Making / Q000502:physiology*; D007174:Disruptive, Impulse Control, and Conduct Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D004298:Dopamine / Q000378:metabolism; D005260:Female; D005715:Gambling / Q000523:psychology*; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008032:Limbic System / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009415:Nerve Net / Q000503:physiopathology; D010300:Parkinson Disease / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology* / Q000523:psychology; D012201:Reward; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology
D000978:Antiparkinson Agents; D004298:Dopamine