Evidence-based analysis of the worldwide abuse of licit and illicit drugs.

In order to place the issues of drug abuse in a proper perspective and to allow rational, evidence-based decision-making, an analysis of the international data on the use of illicit drugs and the misuse of legally prescribed psychotropic drugs was undertaken. The data show that by far the most widely abused drug is cannabis, followed, according to region, by amphetamine-type stimulants or cocaine. While opiate abuse is far less widespread, it accounts for a disproportionately large proportion of medical and social problems. The illicit use of licit medicines is a very small, and declining, problem. The implications of these data for physicians, politicians, regulators and administrators are discussed.