I'd say that's quite an understatement. I think there ought to be a mountain of research in a continuous chain going back to the time of O'Shaughnessy in the 19th century.

If you learn about this one thing then you learn something about virtually all the countries (the 186 parties.)

https://en.wikipedia.org/wiki/Single_Convention_on_Narcotic_Drugs

The Single Convention on Narcotic Drugs, 1961 is an international treaty that controls activities of specific narcotic drugs and lays down a system of regulations for their medical and scientific uses; it also establishes the International Narcotics Control Board. Condition: 40 ratifications Effective: 13 December 1964 (original text); 8 August 1975 (as amended in 1972) Parties: 186 (as of 2022) Signed: 30 March 1961; 8 August 1972 (amendment)

https://www.unodc.org/unodc/en/commissions/CND/Mandate_Functions/Scheduling.html

The Commission on Narcotic Drugs is mandated to decide on the scope of control of substances under the three 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.

States parties to these conventions are required to ensure that the respective mandatory control measures are applied to substances listed in the schedules for the 1961 Convention, the schedules of the 1971 Convention and the tables for the 1988 Convention which are annexed to these conventions. During its sessions, the Commission on Narcotic Drugs decides on proposals to add substances to, or to transfer or delete substances from the schedules/tables. The schedules/tables entail different levels of control measures.