Drug: any chemical entity or mixture, other than those required for the maintenance of normal health (such as food), which alters biological function or structure where administered. In 2017, 5% of the world's adult population (250 million people) report using an illicit drug at least once. The United States has 4.4% of the world's population, but consumes 65% of the world's supply of illicit drugs and a 1/4 of drug related deaths. Substance Abuse and Mental Health Administration Survey Age: