Advances in the neurobiology of drug addiction have led to the identification of neuronal substrates responsible for the rewarding effects of prototypical drugs of abuse, which are crucial to the addictive process. There is increasing evidence that prolonged exposure to drugs of abuse produces long-lasting effects in cognitive and drug-rewarding circuits. For this reason, addiction should be considered a chronic medical illness.97,98 Symptoms of withdrawal can be treated, and maintenance therapy is available for most drugs of abuse,43,98-101 but the development of long-term strategies based on medication, psychosocial support, and continued monitoring97,98 is a challenging clinical goal.