Convention on Psychotropic Substances

Convention on Psychotropic Substances

Convention on Psychotropic Substances, 1971

Instrument

Type	Treaty
Number	United Nations Treaty Series, vol. 1019, p. 175
Jurisdiction	International
Adopted	21 February 1971
Place	Vienna
In force from	16 August 1976
Parties	184 (October 2026)
Depositary	Secretary-General of the United Nations

Status

Status	In force

Cannabis

No provision on the cannabis plant or its cultivation; isomers of tetrahydrocannabinol are in Schedule I and delta-9-tetrahydrocannabinol (dronabinol) is in Schedule II

Text

Read the official text

The Convention on Psychotropic Substances is the United Nations treaty of 1971 on the control of psychotropic substances, the substances listed in its four schedules. Its parties limit the use of these substances to medical and scientific purposes. Those in Schedule I are subject to the special provisions of article 7.^{: arts. 5, 7} A conference in Vienna adopted it on 21 February 1971. It came into force on 16 August 1976. In October 2026 it had 184 parties.

The Convention controls no part of the cannabis plant and has no provision on its cultivation. Cannabis and cannabis resin stay under the 1961 Single Convention on Narcotic Drugs.^{: 3, 39} Its cannabis content is two entries in its schedules: isomers of tetrahydrocannabinol (THC) in Schedule I and delta-9-tetrahydrocannabinol in Schedule II.^: 5–6 In 2019 the World Health Organization (WHO) recommended moving both entries to the Single Convention. On 2 December 2020 the Commission on Narcotic Drugs rejected the addition of delta-9-tetrahydrocannabinol (dronabinol) to the Single Convention and therefore did not vote on the deletions from this Convention, so both entries remain.^: v–vi

Background and drafting

The Economic and Social Council convened the United Nations Conference for the Adoption of a Protocol on Psychotropic Substances by resolution 1474 (XLVIII) of 24 March 1970. It met in Vienna from 11 January to 21 February 1971 with 71 states represented.^{: Final Act, paras. 1–3} The Convention defines the International Narcotics Control Board as the Board "provided for in the Single Convention on Narcotic Drugs, 1961". It leaves decisions on the schedules to the Commission on Narcotic Drugs, on the assessment of the WHO.^{: arts. 1(b)–(c), 2}

In the account of Bewley-Taylor, Blickman and Jelsma (2014), the WHO Expert Committee discussed a draft of the treaty in 1970 and recommended placing the tetrahydrocannabinols in its strictest category. The pharmaceutical industry, interested in the medical potential of the cannabinols, preferred to see them controlled under a new treaty, apart from the controls the Single Convention placed on cannabis. The conference argued several times over how to separate the control of cannabis from the control of its active principles. It dropped all references to "production" so that cannabis, the plant from which the tetrahydrocannabinols were derived, would not fall within the treaty.^: 22–23

Cannabis in the text

Substances, not plants

Article 1(e) reads: "'Psychotropic substance' means any substance, natural or synthetic, or any natural material in Schedule I, II, III or IV."^{: art. 1(e)} The UN Commentary of 1976 takes "natural material" to mean parts of a plant which themselves constitute a psychotropic substance.^: 11–12 It adds that plants as such are not listed in Schedule I, only some products obtained from them, so that article 7 and the other provisions of the Convention do not apply to the plants from which Schedule I substances may be obtained.^: 385

The Convention has no definition of cultivation. The Commentary notes that it "does not contain any provision governing the cultivation of plants from which substances which it controls may be obtained".^: 3 It also has no separate category of "production", the term the Single Convention uses for separating opium, coca leaves, cannabis and cannabis resin from the plants that yield them. Every process by which a psychotropic substance is obtained is "manufacture". The Commentary counts the harvesting of a psychotropic substance from a plant as manufacture. Cultivating the plant is not manufacture.^{: 3, 24–25}

Cannabis stays in the Single Convention

Article 2(1) lets a party or the WHO notify a substance "not yet under international control" for addition to the schedules.^{: art. 2(1)} The Commentary argues that the phrase refers to control by the Single Convention, so that no party would have to apply both treaties to the same substance. In its reading, the Commission could delete cannabis or cannabis resin from the Single Convention's schedules, but could not free the plant from that treaty's controls on cultivation or the drugs from its controls on production, which only an amendment could change. Placing cannabis under both treaties would make the harvest subject to two regimes at once, so cannabis and cannabis resin could not be moved from the Single Convention to this one without amending the Single Convention.^: 37–39

Tetrahydrocannabinol in the schedules

Schedule I as adopted listed ten substances. The tenth was "tetrahydrocannabinols", followed by a single chemical name.^: 328 The Commentary, which prints the entry as "tetrahydrocannabinols, all isomers", notes that the conference included no isomers in the schedules except those of the tetrahydrocannabinols.^{: 23, 392, 394}

For a substance in Schedule I, article 7 requires parties to "prohibit all use except for scientific and very limited medical purposes by duly authorized persons" in establishments under government control or approved by government. Manufacture, trade, distribution and possession need a special licence or prior authorisation. Export and import are limited to authorised bodies.^{: art. 7} For Schedule II, article 5(2) requires parties to limit manufacture, trade, possession and use to medical and scientific purposes. Article 9 requires that they be supplied to individuals only on medical prescription.^{: arts. 5(2), 9}

In the 2025 list of the International Narcotics Control Board, Schedule I holds "tetrahydrocannabinol, the following isomers and their stereochemical variants": delta-6a(10a)-THC, delta-6a(7)-THC, delta-7-THC, delta-8-THC, delta-10-THC and delta-9(11)-THC. Schedule II holds "delta-9-tetrahydrocannabinol and its stereochemical variants".^: 5–6 The UNODC text of the Convention lists the Schedule II entry under the name DRONABINOL, with a note that this name "refers to only one of the stereochemical variants of delta-9-tetrahydrocannabinol, namely (-)- trans-delta-9-tetrahydrocannabinol".^{: Schedule II} The 2025 list also added hexahydrocannabinol (HHC) to Schedule II.^: 1

Amendment and scheduling history

Under article 2 the WHO assesses a substance. Its assessment is "determinative as to medical and scientific matters". The Commission on Narcotic Drugs decides whether to add a substance to a schedule, move it or delete it. A decision becomes fully effective for each party 180 days after the Secretary-General communicates it.^{: art. 2(4)–(7)}

Delta-9-THC and dronabinol

In 1989 the WHO Expert Committee on Drug Dependence recommended moving dronabinol alone to Schedule II, leaving the other isomers and stereochemical variants in Schedule I. The Commission rejected the proposal at its 11th special session in 1990. The Expert Committee then recommended moving delta-9-THC with all its stereochemical variants, so that they would not sit in different schedules. The Commission adopted this at its 34th session in 1991.^: 8–9

Three later recommendations to move dronabinol further did not take effect. In 2002 the Expert Committee recommended Schedule IV, but the recommendation was not communicated to the Commission. In 2006 it recommended Schedule III. In March 2007 the Commission decided by consensus not to vote and asked the WHO for a new review when more information became available (decision 50/2). The Expert Committee restated the Schedule III recommendation in 2012. In March 2014 the Commission voted against it.^: 9–10

The 2019 recommendations and the 2020 vote

The Expert Committee's 41st meeting, held in Geneva in November 2018, reviewed cannabis and the substances related to it. In a letter of 24 January 2019 the WHO Director-General recommended adding dronabinol to Schedule I of the Single Convention and deleting it from Schedule II of this Convention. It also recommended adding the isomers of delta-9-THC to Schedule I of the Single Convention and deleting them from Schedule I of this Convention. Each deletion was made subject to the matching addition. Both recommendations on the isomers depended on the adoption of the one on dronabinol.

The Commission voted on 2 December 2020. Its voting procedure provided that if the addition of dronabinol to the Single Convention was rejected, the deletion of dronabinol and the two recommendations on the isomers would not be voted on, "in order to avoid having a substance scheduled under two conventions".^: 3–4 The Commission rejected the addition of dronabinol by 23 votes to 28, with 2 abstentions (decision 63/18). It therefore did not vote on the recommendations concerning this Convention.^{: v–vi, 5}

Implementation

Article 22(1)(a) requires each party, subject to its constitutional limitations, to treat as a punishable offence any intentional action contrary to a law or regulation adopted under the Convention, with serious offences liable to "adequate punishment, particularly by imprisonment or other penalty of deprivation of liberty". Under article 22(1)(b) parties may provide treatment, education, after-care, rehabilitation and social reintegration for "abusers of psychotropic substances", as an alternative or an addition to conviction or punishment.^{: art. 22(1)}

Effect on cultivation and traditional use

The Commentary of 1976 suggests that, although the Convention does not control cultivation, growing a plant from which a psychotropic substance may be obtained could be treated under article 22(2)(a)(ii) as an attempt to commit an offence or as an act preparatory to one.^{: 25, 359} Bewley-Taylor, Blickman and Jelsma (2014) write that cultivation, production and plants were "deliberately kept out of the treaty". On that ground they call it a terminological error when resolutions of the Commission speak of the "illicit cultivation of crops used for the production of narcotic drugs and psychotropic substances".^{: 23, 31}

Reception

Bewley-Taylor, Blickman and Jelsma (2014) argue that by controlling THC under this Convention while the plant stayed under the Single Convention, "the basic rationale of the Single Convention was abandoned" for cannabis. They describe the Commission's decision of 1991 to move delta-9-THC to Schedule II as the first step towards formal acknowledgement at the UN of the medical usefulness of the main active compound of cannabis.^: 22–23

See also

• Commission on Narcotic Drugs
• International Narcotics Control Board
• Single Convention on Narcotic Drugs
• Tetrahydrocannabinol
• United Nations Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances