Habit Learning and Addiction

Drug addiction is a chronic compulsion and relapsing disorder defined as a “pathological pattern of use of a substance”, and characterized by the loss of control in drug-taking-related behaviors, the pursuance of those behaviors even in the presence of negative consequences, and a strongly motivated desire to consume substances. Several brain areas and circuits are involved, encoding cognitive functions such as reward, motivation, and memory. Addiction research has moved the focus to those psycho-neurobiological mechanisms that have a crucial role on the transition from an occasional use to the abuse of drugs. It has been hypothesized that drug addiction may start as a “goal-directed behavior”; later, with the maintenance of the “instrumental behavior”, it can turn into a “habitual behavior”, inducing a form of habit-based learning. At a brain level, it has been suggested that DA-ergic/GLU-ergic/NE-ergic meso-cortico-limbic transmission may have a crucial role in the pathological habit-based learning of a drug-seeking behavior.