Introduction
Alcohol addiction is one of the biggest problems of modern society through its impact on health, social cohesion, crime, and its comorbidity with other neuropsychiatric disorders. Major advances in genetics and molecular neurobiology have led to the identification of many of the primary targets of alcohol and revealed neuroadaptations that develop with its chronic consumption. However, understanding pre-existing cognitive deficits that serve as substrates compounding the initiation of alcohol use and the development of alcohol use disorder (AUD) remains a major challenge.
All goal-directed behaviours, including alcohol use and abuse, are composed of two core components: the decision-making process, which starts with representations of the available options that lead to the selection of the option with the highest expected value, and reinforcement learning, through which outcomes are used to refine value expectations. The decisions based on the above-mentioned processes are often biased by an abnormal sensitivity to positive and negative reinforcement, which results in abnormal sensitivity to performance feedback, skewed interpretations of ambiguity, inflated expectations, and asymmetrical belief updating. We have defined this abnormal cognitive processing as reinforcement-based cognitive biases (RBCBs). While the investigation of cognitive biases has a long history in economics and psychology, RBCBs in the context of AUD have been much less systematically investigated and, perhaps, neglected. This is surprising, as most of the decisions regarding alcohol-related behaviours are related to their positive and negative reinforcing effects. Although the causal role of the RBCBs in AUD has been emphasized by various psychological theories and investigating the interrelations between biased cognition and AUD could become a thriving area of research that capitalizes on the newest advances in cognitive neuroscience, psychology, and psychiatry, studying the nature and the extent to which RBCBs play a role in the development and maintenance of alcohol addiction still faces formidable methodological obstacles and does not provide definite answers regarding underlying mechanisms.
In this review, we first briefly describe psychological and cognitive theories that implicated various aspects of reinforcement-biased cognition in the development, maintenance, and recurrence of alcohol addiction. Furthermore, in separate sections, we describe recent studies investigating the RBCBs, their neural, neurochemical, and pharmacological correlates, and possible interactions between RBCBs and trajectories of AUD. Finally, we describe how recent translational studies using state-of-the-art animal models could facilitate our understanding of the role of reinforcement sensitivity and RBCBs in various aspects of AUD.