Objective: The purpose of this article is to review some of the basic aspects of the dopaminergic system and its role in reward and pleasure behaviour. We also discuss the association between dopamine and unpleasant symptoms that are commonly found in neuropsychiatric disorders and may also be side-effects of neuroleptic drugs.
Method: A computer-based search of the literature, augmented by extensive bibliography-guided article reviews, were used to find basic information on the dopamine and the reward systems, and symptoms such as dysphoria, anhedonia and depression.
Results: Central dopaminergic neurotransmission is complex, having multiple actions at each level of the mesocorticolimbic reward pathway. The role of dopamine in the reward process was classically associated with the ability to experience pleasure; recent data suggest a more motivational role. Dysfunction of the dopamine transmission in the reward circuit is associated with symptoms such as anhedonia, apathy and dysphoria found in several neuropsychiatric disorders, including Parkinson's disease, depression, drug addiction, and neuroleptic-induced dysphoria.
Conclusion: Viewing the dysfunctions of the reward pathways within a broader spectrum and exploring its complex relations with the dopaminergic transmission may help understand the pathophysiology of these neuropsychiatric disorders and lead to a rational development of novel treatments.