What motivates gambling behaviour? Insight into dopamine’s role

It is commonly believed that monetary gain is the cause of gambling behaviour in humans. Mesolimbic dopamine (DA), the chief neuromediator of incentive motivation, is indeed released to a larger extent in pathological gamblers (PG) than in healthy controls (HC) during gambling episodes (Joutsa et al., 2012; Linnet et al., 2011), as in other forms of compulsive and addictive behaviour. However, recent findings indicate that the interaction between DA and reward is not so straightforward (Blum et al., 2012; Linnet et al., 2012). In PG and HC, DA release seems to reflect the unpredictability of reward delivery rather than reward per se. This suggests that the motivation to gamble is strongly (though not entirely) determined by the inability to predict reward occurrence. Here we discuss several views of the role of DA in gambling, and attempt to provide an evolutionary framework to explain its role in uncertainty.