International control

International control is the placement of a substance on a schedule of one of the United Nations drug-control treaties, creating an obligation for signatory states to restrict its production, trade, and use. The two primary instruments are the 1961 Single Convention on Narcotic Drugs, covering opioids, cannabis, and coca-related substances, and the 1971 Convention on Psychotropic Substances, covering hallucinogens, stimulants, and sedative-hypnotics. Each treaty uses four schedules, with Schedule I carrying the strictest controls.

The scheduling process begins with a recommendation from the WHO Expert Committee on Drug Dependence, which assesses a substance's medical use and abuse potential. The Commission on Narcotic Drugs — the UN body that administers the treaties — then votes on whether to add, move, or remove a substance.

What it means in practice

International control does not create a single global drug law. It imposes treaty obligations on the majority of UN member states to enact their own legislation restricting scheduled substances. The treaties set a floor: a signatory may apply stricter controls than the treaty requires but is not permitted to fall below it for trade and supply.

Placement in Schedule I of the 1971 Convention requires parties to prohibit manufacture, trade, and possession except under licence for scientific or medical purposes. Substances can also be rescheduled: in December 2020, the Commission on Narcotic Drugs voted to remove cannabis from Schedule IV of the 1961 Convention — the tier reserved for substances considered particularly dangerous and of limited medical utility — while retaining it in Schedule I.

How jurisdictions vary

Schedule numbers do not translate across legal systems. Schedule I of the 1971 Convention (the most restrictive tier) is a different legal object from Schedule I of the US Controlled Substances Act, which turns on different statutory criteria and carries different legal consequences. The UK's Misuse of Drugs Act uses Class A, B, and C rather than numbered schedules entirely.

Some countries that have ratified the conventions have enacted personal-use decriminalization, treating the treaties as compatible with removing criminal penalties for possession while maintaining supply controls. Portugal is a widely cited example. Others read the same treaty obligations as requiring criminal sanctions for possession.

What is contested

Several substances scheduled under the 1971 Convention at levels that restrict research have been studied in clinical trials for conditions including treatment-resistant depression and post-traumatic stress disorder. In these cases the published evidence and the legal classification have diverged.

The phrase no currently accepted medical use appears in some national implementing statutes — most prominently the US Controlled Substances Act — as a criterion for the most restrictive scheduling tier. It is a legal classification, not a scientific finding, and it can persist even as clinical trial evidence accumulates. It also does not appear verbatim in the 1971 Convention's own scheduling criteria, which address abuse potential and risk to public health.

Scope and currency

This entry is not legal advice and does not describe the law in any particular jurisdiction. It states the position as of August 2026. The per-substance legal status section on each substance page carries jurisdiction-specific information with its own date and source — rely on that section, not this entry, for any practical assessment of a substance's legal status where you are.