In recent years, the malady of drug abuse has spread its tentacles in almost every sphere of public life and has had a large array of corrosive effects on the societies in which it has been most rampant. The reason why the problem of drug abuse is viewed as a far more serious problem than other social evils is because it is inextricably intertwined with other offences such as organized crimes, human trafficking and money laundering as well as health hazards such as HIV -AIDS.

The three main international drug control conventions are:

1. the Single Convention on Narcotic Drugs of 1961 as amended by the 1972 Protocol
2. the Convention on Psychotropic Substances of 19712 and
3. the United Nations Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988.

The Single Convention on Narcotic Drugs of 1961 is an international treaty to prohibit production and supply of specific (nominally narcotic) drugs and of drugs with similar effects except under licence for specific purposes, such as medical treatment and research. Its major effects included updating the Paris Convention of 1931 to include the vast number of synthetic opioids invented in the intervening thirty years and a mechanism for more easily including new ones. From 1931 to 1961, most of the families of synthetic opioids had been developed.

Earlier treaties had only controlled opium, coca, and derivatives such as morphine, heroin and cocaine. The Single Convention, adopted in 1961, consolidated those treaties and broadened their scope to include cannabis and drugs whose effects are similar to those of the drugs specified. The Commission on Narcotic Drugs and the World Health Organization were empowered to add, remove, and transfer drugs among the treaty's four schedules of controlled substances.

The International Narcotics Control Board was put in charge of administering controls on drug production, international trade, and dispensation. The United Nations Office on Drugs and Crime (UNODC) was delegated the Board's day-to-day work of monitoring the situation in each country and working with national authorities to ensure compliance with the Single Convention. This treaty has since been supplemented by the Convention on Psychotropic Substances, which controls LSD, MDMA, and other psychoactive pharmaceuticals, and the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances, which strengthens provisions against money laundering and other drug-related offenses.

As of February 2018, the Single Convention has 186 state parties.

History:
The League of Nations adopted several drug control treaties prior to World War II, such as the International Opium Convention, and International Convention relating to Dangerous Drugs (1925) specifying uniform controls on addictive drugs such as cocaine and opium, and its derivatives. However, the lists of substances to be controlled were fixed in the treaties' text; consequently, it is necessary to periodically amend or supersede the conventions through the introduction of new treaties to keep up with advances in chemistry. In a 1954 interview the United States Commissioner Of Narcotics at the time stated that the cumbersome process of conference and state-by-state ratification could last for a period of numerous decades.

The work of consolidating the existing international drug control treaties into one instrument began in 1948, but it was 1961 before an acceptable third draft was ready. That year, the UN Economic and Social Council convened a conference of 73 nations for the adoption of a single convention on narcotic drugs. That meeting was known as the United Nations Conference on Narcotic Drugs. After 8 weeks of negotiations finally a compromise treaty was produced. Several controls were watered down. A compromise was also struck that allowed heroin and some other drugs classified as particularly dangerous to escape absolute prohibition.

The Single Convention created four Schedules of controlled substances and a process for adding new substances to the Schedules without amending the treaty. The Schedules were designed to have significantly stricter regulations than the two drug Groups established by predecessor treaties. For the first time, cannabis was added to the list of internationally controlled drugs. In fact, regulations on the cannabis plant - as well as the opium poppy, the coca bush, poppy straw and cannabis tops - were embedded in the text of the treaty, making it impossible to deregulate them through the normal Scheduling process.

The Single Convention entered into force on 13 December 1964, having met Article 41's requirement of 40 ratifications. As of 1 January 2005, 180 states were Parties to the treaty. On 21 May 1971, the UN Economic and Social Council called a conference of to consider amendments to the Single Convention. The conference met at the United Nations Office at Geneva for 18 days producing the 1972 Protocol Amending the Single Convention on Narcotic Drugs. The amendments entered into force on 8 August 1975.

Medicinal and other drug uses:
The Single Convention repeatedly affirms the importance of medical use of controlled substances. The Preamble notes 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.

Articles 1, 2, 4, 9, 12, 19, and 49 contain provisions relating to medical and scientific use of controlled substances. In almost all cases, parties are permitted to allow dispensation and use of controlled substances under a prescription, subject to record-keeping requirements and other restrictions.

The Single Convention takes a prohibitionist approach to the problem of drug addiction, attempting to stop all non-medical, non-scientific use of narcotic drugs. Article 4 requires nations to limit use and possession of drugs to medicinal and scientific purposes. Article 49 allows countries to phase out coca leaf chewing, opium smoking, and other traditional drug uses gradually, but provides that the use of cannabis for other than medical and scientific purposes must be discontinued as soon as possible.

The discontinuation of these prohibited uses is intended to be achieved by cutting off supply. Rather than calling on nations to prosecute drug users, the treaty focuses on traffickers and producers. As of 2013, 234 substances are controlled under the Single Convention.

Penal Provisions:
Article 36 requires Parties to adopt measures against cultivation, production, manufacture, extraction, preparation, possession, offering, offering for sale, distribution, purchase, sale, delivery on any terms whatsoever, brokerage, dispatch, dispatch in transit, transport, importation and exportation of drugs contrary to the provisions of this Convention, as well as intentional participation in, conspiracy to commit and attempts to commit, any of such offences, and preparatory acts and financial operations in connexion with the offences referred to in this article. Article 36 does not directly require criminalization of all the above; it states only in the cases of (unspecified) serious offences that they shall be liable to adequate punishment particularly by imprisonment or other penalties of deprivation of liberty.

The Article also provides for extradition of drug offenders, although a Party has a right to refuse to extradite a suspect if competent authorities consider that the offense is not sufficiently serious. A 1971 amendment to the Article grants nations the discretion to substitute treatment, education, after-care, rehabilitation and social reintegration for criminal penalties if the offender is a drug abuser. A loophole in the Single Convention is that it requires Parties to place anti-drug laws on the books, but does not clearly mandate their enforcement, except in the case of drug cultivation.

The Single Convention's penal provisions frequently begin with clauses such as Subject to its constitutional limitations, each Party shall ... Thus, if a nation's constitution prohibited instituting the criminal penalties called for by the Single Convention, those provisions would not be binding on that country.

Possession for personal use:
It is unclear whether or not the treaty requires criminalization of drug possession for personal use. The treaty's language is ambiguous, and a ruling by the International Court of Justice would probably be required to settle the matter decisively. However, several commissions have attempted to tackle the question. With the exception of the Le Dain Commission, most have found that states are allowed to legalize possession for personal use.

Schedules of Drugs:
The Single Convention's Schedules of drugs range from most restrictive to least restrictive, in this order: Schedule IV, Schedule I, Schedule II, Schedule III. The list of drugs initially controlled was annexed to the treaty. Article 3 states that in order for a drug to be placed in a Schedule, the World Health Organization must make the findings required for that Schedule as follows:
Schedule I - The substance is liable to similar abuse and productive of similar ill effects as the drugs already in Schedule I or Schedule II, or is convertible into a drug.
Schedule II - The substance is liable to similar abuse and productive of similar ill effects as the drugs already in Schedule I or Schedule II, or is convertible into a drug.
Schedule III - The preparation, because of the substances which it contains, is not liable to abuse and cannot produce ill effects; and the drug therein is not readily recoverable.
Schedule IV - The drug, which is already in Schedule I, is particularly liable to abuse and to produce ill effects, and such liability is not offset by substantial therapeutic advantages.

Schedule I is the category of drugs whose control provisions constitute the standard regime under the Single Convention such as Limitation to medical and scientific purposes of all phases of narcotics trade, requirement of governmental authorization (licensing or state ownership) of participation in any phase of the narcotics trade, to keep detailed records of parties’ transactions in drugs, requirement of a medical prescription for the supply of drugs to individuals, etc.

Schedule II drugs are regulated only slightly less strictly than Schedule I drugs. Drugs in Schedule II are subject to the same measures of control as drugs in Schedule I, with only a few exceptions.

Schedule III contains preparations which enjoy a privileged position under the Single Convention, i.e. are subject to a less strict regime than other Preparations.

Schedule IV is the category of drugs, such as heroin, that are considered to have particularly dangerous properties in comparison to other drugs (ethanol is left unregulated). According to Article 2, The drugs in Schedule IV shall also be included in Schedule I and subject to all measures of control applicable to drugs in the latter Schedule as well as whatever special measures of control; each Party deems necessary.

Power structure:
The Single Convention gives the UN Economic and Social Council's Commission on Narcotic Drugs (CND) power to add or delete drugs from the Schedules, in accordance with the World Health Organization's findings and recommendations. Any Party to the treaty may request an amendment to the Schedules, or request a review of the Commission's decision.

The Economic and Social Council is the only body that has power to confirm, alter, or reverse the CND's scheduling decisions. The United Nations General Assembly can approve or modify any CND decision, except for scheduling decisions. The CND's annual meeting serves as a forum for nations to debate drug policy.

The International Narcotics Control Board (INCB) is mandated by Article 9 of the Single Convention to endeavour to limit the cultivation, production, manufacture and use of drugs to an adequate amount required for medical and scientific purposes, to ensure their availability for such purposes and to prevent illicit cultivation, production and manufacture of, and illicit trafficking in and use of, drugs. The INCB administers the estimate system, which limits each nation's annual production of controlled substances to the estimated amounts needed for medical and scientific purposes.

Article 14 authorizes the INCB to recommend an embargo on imports and exports of drugs from any noncompliant nations. The INCB can also issue reports critical of noncompliant nations, and forward those reports to all Parties.

Article 21 provides that the total of the quantities of each drug manufactured and imported by any country or territory in any one year shall not exceed the sum of the quantity:

1. Consumed, within the limit of the relevant estimate, for medical and scientific purposes;
2. Used, within the limit of the relevant estimate, for the manufacture of other drugs, of preparations in Schedule Ill, and of substances not covered by this Convention;
3. Exported;
4. Added to the stock for the purpose of bringing that stock up to the level specified in the relevant estimate; and
5. Acquired within the limit of the relevant estimate for special purposes.

Article 21 bis, added to the treaty by a 1971 amendment, gives the INCB more enforcement power by allowing it to deduct from a nation's production quota of cannabis, opium, and coca the amounts it determines have been produced within that nation and introduced into the illicit traffic.

This could happen as a result of failing to control either illicit production or diversion of licitly produced opium to illicit purposes. In this way, the INCB can essentially punish a narcotics-exporting nation that does not control its illicit traffic by imposing an economic sanction on its medicinal narcotics industry.

The Single Convention exerts power even over those nations that have not ratified it. Article 48 designates the International Court of Justice as the arbiter of disputes about the interpretation or application of the Single Convention, if mediation, negotiation, and other forms of alternative dispute resolution fail.

Limitation of scope:
The Single Convention allows only drugs with morphine-like, cocaine-like, and cannabis-like effects to be added to the Schedules. The strength of the drug is not relevant; only the similarity of its effects to the substances already controlled. Whereas on the other hand the Convention on Psychotropic Drugs' scope can include any drug not already under international control if the World Health Organization finds that there is sufficient evidence that the substance is being or is likely to be abused so as to constitute a public health and social problem warranting the placing of the substance under international control.

The reason for sharply limiting the scope of Single Convention to a few types of drugs while letting the Convention on Psychotropic Drugs cover the rest was concern for the interests of industry. Concerted efforts by drug manufacturing nations and the pharmaceutical industry ensured that the controls on psychotropics in the 1971 treaty were considerably looser than those applied to organic drugs in the Single Convention.

Furthermore, the provisions of the Single Convention regarding the national supply and demand of opium to make morphine contribute to the global shortage of essential poppy-based pain relief medicines.

According to the Convention, governments can only request raw poppy materials according to the amount of poppy-based medicines used in the two preceding years. Consequently, in countries where under prescription is chronic due to the high prices of morphine and lack of availability and medical training in the prescription of poppy-based drugs, it is impossible to demand enough raw poppy materials from the INCB, as the Convention's regulating body, to meet the country's pain relief needs.

As such, 77% of the world's poppy-based medicine supplies are used by only six countries. Many critics of the Convention cite this as one of its primary limitations and the World Health Organization is currently attempting to increase prescription of poppy-based drugs and to help governments of emerging countries in particular alter their internal regulations to be able to demand poppy-based medicines according to the Convention's provisions.

Regulation of Cannabis:
The Single Convention places the same restrictions on cannabis cultivation that it does on opium cultivation. Article 23 and Article 28 require each Party to establish a government agency to control cultivation. Cultivators must deliver their total crop to the agency, which must purchase and take physical possession of them within four months after the end of harvest. The agency then has the exclusive right of importing, exporting, wholesale trading and maintaining stocks other than those held by manufacturers. Article 28 specifically excludes industrial hemp from these regulations, stating, This Convention shall not apply to the cultivation of the cannabis plant exclusively for industrial purposes (fibre and seed) or horticultural purposes.

There is some controversy over whether cannabis is particularly liable to abuse and to produce ill effects and whether that liability is not offset by substantial therapeutic advantages, as required by Schedule IV criteria. At the U.S.'s insistence, cannabis was placed under the heaviest control regime in the Convention, Schedule IV. The argument for placing cannabis in this category was that it was widely abused. The WHO later found that cannabis could have medical applications after all, but the structure was already in place and no international action has since been taken to correct this anomaly.

Some question has been raised whether the use of the plant itself produces severe psychological or physical dependence as required by a schedule I or even schedule II criterion. The Single Convention defines cannabis as the flowering or fruiting tops of the cannabis plant (excluding the seeds and leaves when not accompanied by the tops) from which the resin has not been extracted. (Art. 1, s-para. 1(b))

It is generally accepted that this definition permits the legalization of the leaves of the cannabis plant, provided that they are not accompanied by the flowering or fruiting tops. However, uncertainty arises by virtue of paragraph 3 of Article 28 which requires parties to the Convention to adopt such measures as may be necessary to prevent the misuse of, and illicit traffic in, the leaves of the cannabis plant.

In summary, it appears that parties are not obliged to prohibit the production, distribution and use of the leaves (since they are not drugs, as defined the Convention), although they must take necessary, although unspecified, measures to prevent their misuse and diversion to the illicit trade.

Predecessor treaties:
Article 44 provided that the Single Convention's entry into force terminated several predecessor treaties, including the International Opium Convention, 1912; the International Opium Convention, 1925; the Convention for Limiting the Manufacture and Regulating the Distribution of Narcotic Drugs, 1931; The Protocol for Limiting and Regulating the Cultivation of the Poppy Plant, the Production of, International and Wholesale Trade in, and Use of Opium, 1953 among other treaties.

Supplementary treaties:
The Single Convention is supplemented by two other major drug control treaties:

• The Convention on Psychotropic Substances controls LSD, MDMA, and other drugs whose unique psychoactive effects exclude them from the scope of the Single Convention. It was signed at Vienna on 21 February 1971.
   
• The United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances adds additional enforcement mechanisms for fighting drug traffickers, including asset forfeiture provisions. It was signed at Vienna on 20 December 1988.

Conclusion:
The Convention also has an influence on the domestic laws of the Parties. Since the Single Convention is not self-executing, Parties must pass laws to carry out its provisions, and the UNODC works with countries' legislatures to ensure compliance. As a result, most of the national drug statutes in the UNODC's legal library share a high degree of conformity with the Single Convention and its supplementary treaties. The Single Convention has been used as the basis for the standardization of national drug-control laws.