The article discusses the neurobiology of addiction, focusing on the persistent state of compulsive drug use despite negative consequences. It highlights the molecular and cellular mechanisms of tolerance, dependence, and withdrawal, but notes that the neural substrates of compulsive drug use and its persistence are less understood. The authors suggest that compulsion and its persistence may be based on the pathological usurpation of molecular mechanisms involved in memory. They review evidence that addictive drugs alter neural circuits, particularly the dopaminergic system, which is crucial for reward and reinforcement. The article also explores the role of dopamine in learning and memory, and the potential involvement of synaptic plasticity, such as long-term potentiation (LTP) and long-term depression (LTD), in the development of addiction. Finally, it discusses candidate molecular mechanisms, including the upregulation of certain proteins and genes, that may contribute to the persistence of addiction. The authors emphasize the need for interdisciplinary research to better understand the complex mechanisms underlying addiction and to develop more effective treatments.The article discusses the neurobiology of addiction, focusing on the persistent state of compulsive drug use despite negative consequences. It highlights the molecular and cellular mechanisms of tolerance, dependence, and withdrawal, but notes that the neural substrates of compulsive drug use and its persistence are less understood. The authors suggest that compulsion and its persistence may be based on the pathological usurpation of molecular mechanisms involved in memory. They review evidence that addictive drugs alter neural circuits, particularly the dopaminergic system, which is crucial for reward and reinforcement. The article also explores the role of dopamine in learning and memory, and the potential involvement of synaptic plasticity, such as long-term potentiation (LTP) and long-term depression (LTD), in the development of addiction. Finally, it discusses candidate molecular mechanisms, including the upregulation of certain proteins and genes, that may contribute to the persistence of addiction. The authors emphasize the need for interdisciplinary research to better understand the complex mechanisms underlying addiction and to develop more effective treatments.