The use and abuse of illicit drugs is an ongoing and insidious world problem. Neuroscience research has contributed importantly to understanding drug abuse as a disease of the nervous system. The goal of this course will be to provide a clinical characterization of drug abuse from a human perspective. From there animal models of drug use and addiction will be discussed as a basis for research examining cellular and molecular mechanisms of the effects of drugs on the nervous system. As all drugs of abuse have a common neurobiology, that neurobiology will be examined from a circuit perspective that will include the underlying molecular control. Collectively students should develop a comprehensive view of the problem of drug addiction including prospects for the development of neurobiologically-based therapeutics.