Nora D. Volkow M.D. is Director of the National Institute on Drug Abuse (NIDA) at the National Institutes of Health. NIDA is the world’s largest funder of research on the health aspects of drug use and addiction. Dr. Volkow’s work has been instrumental in demonstrating that drug addiction is a brain disorder. As a research psychiatrist Dr. Volkow pioneered the use of brain imaging to investigate how substance use affects brain functions. In particular her studies have documented that changes in the dopamine system affect the functions of frontal brain regions involved with reward and self-control in addiction. She has also made important contributions to the neurobiology of obesity ADHD and aging.