Under the international drug control conventions, namely the Single Convention on Narcotic Drugs of 1961, as amended by the 1972 Protocol, the Convention on Psychotropic Substances of 1971 and the United Nations Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988, the Commission on Narcotic Drugs is mandated to decide on the scope of control of substances. Substances are placed under international control by including them in one of the schedules of the 1961 or 1971 Convention or one of the tables of the 1988 Convention.