The article provides an overview of the neurobiology of addiction, defining addiction as a compulsion to use alcohol or other drugs (AODs) and the occurrence of withdrawal symptoms upon cessation. It highlights the role of specific brain regions and neural circuits in modulating addiction, including the ventral tegmental area, basal forebrain, nucleus accumbens, and amygdala. The article discusses the mechanisms of reinforcement and neuroadaptation, which are crucial for initiating and maintaining addictive behavior. Reinforcement involves positive and negative reinforcement, while neuroadaptation includes sensitization and counteradaptation. The article also explores the roles of dopamine, opioid, serotonin, and GABA systems in addiction, and the extended amygdala's role in both acute drug actions and motivational aspects of addiction. Finally, it touches on the neurobiological mechanisms underlying protracted abstinence and relapse, emphasizing the importance of understanding these processes for developing effective treatments.The article provides an overview of the neurobiology of addiction, defining addiction as a compulsion to use alcohol or other drugs (AODs) and the occurrence of withdrawal symptoms upon cessation. It highlights the role of specific brain regions and neural circuits in modulating addiction, including the ventral tegmental area, basal forebrain, nucleus accumbens, and amygdala. The article discusses the mechanisms of reinforcement and neuroadaptation, which are crucial for initiating and maintaining addictive behavior. Reinforcement involves positive and negative reinforcement, while neuroadaptation includes sensitization and counteradaptation. The article also explores the roles of dopamine, opioid, serotonin, and GABA systems in addiction, and the extended amygdala's role in both acute drug actions and motivational aspects of addiction. Finally, it touches on the neurobiological mechanisms underlying protracted abstinence and relapse, emphasizing the importance of understanding these processes for developing effective treatments.