Dopaminergic signaling of uncertainty and the aetiology of gambling addiction.

Although there is increasing clinical recognition of behavioral addictions, of which gambling disorder is the prototype example, there is a limited understanding of the psychological properties of (non-substance-related) behaviors that enable them to become 'addictive' in a way that is comparable to drugs of abuse. According to an influential application of reinforcement learning to substance addictions, the direct effects of drugs to release dopamine can create a perpetual escalation of incentive salience. This article focusses on reward uncertainty, which is proposed to be the core feature of gambling that creates the capacity for addiction.