The article explores the neural mechanisms underlying the transition from voluntary drug use to compulsive drug-seeking and addiction. It hypothesizes that this transition involves a shift from prefrontal cortical control to striatal control, particularly from ventral to dorsal striatal regions, mediated by dopaminergic circuits. The authors review evidence suggesting that impulsivity, characterized by low dopamine D2/3 receptors in the nucleus accumbens, predicts both escalated cocaine intake and the switch to compulsive drug-seeking and addiction. They also discuss the role of the dorsal striatum in habit learning and its involvement in relapse after abstinence. The article highlights the importance of understanding the neural mechanisms of addiction, including the interaction between predisposing behavioral traits and chronic drug exposure, to develop effective interventions.The article explores the neural mechanisms underlying the transition from voluntary drug use to compulsive drug-seeking and addiction. It hypothesizes that this transition involves a shift from prefrontal cortical control to striatal control, particularly from ventral to dorsal striatal regions, mediated by dopaminergic circuits. The authors review evidence suggesting that impulsivity, characterized by low dopamine D2/3 receptors in the nucleus accumbens, predicts both escalated cocaine intake and the switch to compulsive drug-seeking and addiction. They also discuss the role of the dorsal striatum in habit learning and its involvement in relapse after abstinence. The article highlights the importance of understanding the neural mechanisms of addiction, including the interaction between predisposing behavioral traits and chronic drug exposure, to develop effective interventions.