In 1961, in an effort to incorporate the discovery and growing use of synthetic opioids such as methadone, as well as cannabis and drugs with similar effects that were not a part of previous treaties, the U.N. developed the Single Convention on Narcotic Drugs.
Prior treaties had only controlled for opium, coca and their derivatives of morphine, heroin and cocaine. In addition to consolidating earlier drug treaties, the 1961 Single Convention was more explicit in its prohibition of the production and supply of illegal drugs except for medical treatment and research. The International Narcotics Control Board (INCB) was given the responsibility for administering the controls for drug production and trade, and the United Nations Office on Drugs and Crime (UNODC) was entrusted with the responsibility to ensure each country’s ongoing compliance.
The 1961 Treaty required cultivator countries to establish national monopolies to centralize and then phase out the cultivation, production, and consumption of coca over 25 years and 15 years for opium. A target date for the complete international prohibition of the nonmedical cultivation and use for coca and opium was set for 1989. The convention further required the immediate enactment of domestic legislation by member countries to prohibit the non-medicinal use of opium, cocaine, and cannabis.