It is widely believed that financial gains are the cause of gambling behavior in humans. Mesolimbic dopamine (DA), the main neuromediator of incentive motivation, is indeed released to a greater extent in pathological gamblers (PG) than in healthy controls (HC) during gambling episodes.
However, recent results indicate that the interaction between DA and reward is not so straightforward. In PG and HC, release by DA appears to reflect the unpredictability of the reward rather than the reward itself. This suggests that game motivation is strongly (though not entirely) determined by the inability to predict the occurrence of the reward. Here we discuss different views of the role of DA in gambling and attempt to provide an evolutionary framework to explain its role in uncertainty.
Front Behav Neurosci. 2013; 7: 182.: What motivates gambling behavior? Insight into dopamine’s role