Addiction is a condition that results in significant harm to the individual and to society more generally. Societies’ response to addiction is influenced by how it is understood. The view that addiction is a choice that individuals make (the choice model) has led to punitive responses to drug use that punish and deter use. Neuroscience research on addiction is challenging politicolegal responses to addiction by suggesting that it is a brain disease that drives individuals to drug use (the medical model). It also promises to lead to more therapeutic responses to addiction and more effective technologies to prevent, counter, or treat it. These possible conceptual effects and therapeutic applications raise important ethical issues.