Scholars generally hold that the synthetic equivalents of the individual components of the cannabis plant are controlled, not by the Single Convention, but by the Convention on Psychotropic Substances of 1971 (the 1971 Convention). The 1972 Convention addresses stimulants, depressants and hallucinogens but not cannabis - and was intended to impose restrictions similar to those established by the Single Convention. Thus, like the Single Convention, it establishes schedules, which determine the relative stringency of restrictions that will apply to a particular substance.
The substances contained in Schedule I are subject to rigorous controls. Specifically, a signatory nation must prohibit all use except for scientific and very limited medical purpose by duly authorized persons, in medical or scientific establishments which are directly under the control of their Governments or specifically approved by them. However, like the Single Convention, the 1972 Convention also recognizes that the use of psychotropic substances for medical and scientific purposes is indispensable and that their availability for such purposes should not be unduly restricted. Therefore, it would seem to contemplate that signatory nations are authorized to allow reasonable access to psychotropic substances for legitimate medical use.
Delta-9-tetrahydrocannabinol (THC) is the primary psychoactive component of cannabis. It has been synthesized as a single-component medicine and, in that form; its availability is governed by the 1972 Convention. Pursuant to that treaty, synthetic THC was originally placed into Schedule I, the most restrictive schedule. However, in 1991, the United Nations Economic and Social Council (ESCOR) rescheduled delta-9-THC to Schedule II.
Synthetic delta-9-THC is available for therapeutic use by prescription. In the United States, it is called dronabinol or Marinol (synthetic THC in sesame seed oil encapsulated in gelatin capsules); in the U.K., an analogue of THC is available as nabilone. In 1999, the U.S. rescheduled Marinol to Schedule III under its domestic law (the Controlled Substances Act) that regulates psychoactive drugs and other substances with abuse potential. Schedule III drugs under U.S. law are subject to fewer restrictions, although a patient must still possess a doctor's prescription. (In order to satisfy the requirements of the 1971 Convention, Marinol is also subject to special import and export controls not applicable to other US Schedule III drugs.)
The Single Convention on Narcotic Drugs of 1961, as amended by the 1972 Protocol Amending the Single Convention on Narcotic Drugs, 1961(the Single Convention) imposes on its signatory nations certain responsibilities regarding the control of cannabis and cannabis resin (hashish). The Single Convention establishes a series of four schedules for narcotic drugs. The placement of a drug in those schedules depends on the perceived risk of abuse that the drug poses. Drugs placed in Schedule I are subject to all measures of control established by the Convention; drugs placed in Schedule IV (the most restrictive schedule) are subject to several additional controls. Cannabis and cannabis resin currently fall within both Schedules I and IV; cannabis tinctures and extracts fall solely within Schedule I. Signatory nations have established domestic scheduling laws that are similar to those contained in the Single Convention.
The Single Convention strictly regulates drugs listed in Schedule IV. However, even as to such drugs, the Single Convention recognizes that legitimate scientific and medical research and treatment uses can, and should, be permitted. Indeed, the treaty explicitly recognizes that 'the medical use of narcotic drugs continues to be indispensable for the relief of pain and suffering and that adequate provision must be made to ensure the availability of narcotic drugs for such purposes.' Similarly, it exhorts nations Ã£to limit exclusively to medical and scientific purposes the production, manufacture, export, import, distribution of, trade in, use and possession of drugs.Ã¤
In order to implement this goal with regard to Schedule IV drugs, the treaty provides several open-ended guidelines. The Single Convention does not require that the availability of cannabis and cannabis resin be limited to research purposes. The treaty states that a nation need limit production of, trade in, and use of a Schedule IV substance to research purposes only 'if in its opinion the prevailing conditions in its country render such a restriction the most appropriate means of protecting the public health and welfare...' Furthermore, a nation need only adopt those 'special measures of control which in its opinion are necessary having regard to the particularly dangerous properties of a drug so included.' Thus, a nation need restrict the availability of a Schedule IV drug to research purposes only if it concludes that such a restriction is 'the most appropriate means' or 'necessary' to the health and safety of its people.
These guidelines give wide discretion to a nation to make a Schedule IV substance available for medical treatment purposes. The official interpretation of the treaty, Commentary on the Single Convention on Narcotic Drugs, 1961, prepared by the Secretary-General of the United Nations, states that the only requirement imposed by these provisions is that the nation act in good faith in determining whether any special measures are needed with regard to Schedule IV drugs. Under these standards, therefore, a nation may conclude that cannabis and cannabis resin (and certainly cannabis tinctures and extracts) should be available for therapeutic use by prescription.
Many countries would likely be interested in making cannabis-based medicines available, if proper clinical trials show that they are safe and efficacious. For example, the United Kingdom Home Office has publicly stated that, if a cannabis-based medicine is approved by the U.K. Medicines Control Agency as safe and efficacious for a particular medical use, the Government would support a change in its domestic law so as to allow doctors to prescribe medicine.
The United States, Canada, and other nation signatories similarly have the authority to amend their domestic laws to make cannabis-based medicines available to patients through a doctor's prescription. The U.S. Drug Enforcement Administration is currently considering a petition that asks the U.S. to remove cannabis and naturally-derived tetrahydrocannabinol from Schedule I of the US Controlled Substances Act. Under US law, cannabis is now available only for research purposes. Canada has announced that it will support clinical trials to determine the therapeutic efficacy of cannabis, as a first step toward making a change in its domestic law.