Drug use is related to adverse health and social outcomes [1]. Cigarette smoking is a leading cause of preventable disability and death in the U.S. and around the world [2], increasing the risk of cancer, cardiovascular disease, respiratory and other health problems [3,4]. The use of other psychoactive substances, most of them illicit drugs, is also associated with massive social cost beyond the damage to the individual users, affecting health care, law enforcement, and legal systems [1,5].
