Addiction is a primary, chronic, neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. Fear of addiction is one of the factors that limits opioid prescribing. Addiction is the traditional term used to identify the irresistible craving for, loss of control over use of, compulsive use of, and continued use despite harm of certain types of drugs. Drugs capable of producing addiction do so by interacting with the biochemistry of the brain in such a way that the drug begins to seem essential—one feels a “need” for it as one does for food and water.