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WHO Expert Committee on Drug Dependence – WHO Technical Report Series, No. 915 – Thirty-third Report
(2003; 31 pages) [French] [Spanish] View the PDF document
Table of Contents
View the document1. Introduction
View the document2. Scheduling criteria
Open this folder and view contents3. Critical review of psychoactive substances
Open this folder and view contents4. Pre-review of psychoactive substances
View the document5. Terminology used in reporting abuse-related adverse drug reactions
View the document6. Other matters
View the documentAcknowledgements
View the documentReferences
View the documentAnnex Terminology used in reporting abuse-related adverse drug reactions

2. Scheduling criteria

In order to ensure consistency in the review process, WHO has developed a formal procedure for its review of dependence-producing psychoactive substances. This procedure has been updated as the need has arisen. The current review procedure follows the guidelines (hereinafter referred to as “the Guidelines”) that were adopted by the Executive Board of WHO in 2000 (1).

The scheduling criteria described in the Guidelines are based on the relevant provisions of the international drug control conventions and additional guiding principles worked out by this Committee at previous meetings. In essence, similarity in terms of abuse and ill effects to drugs already controlled is the criterion applied to narcotic drugs. In accordance with the 1961 Single Convention on Narcotic Drugs (hereinafter referred to as “the 1961 Convention” (2)), the Expert Committee, when deciding whether to recommend international control, first determines whether the substance under review has morphine-like, cocaine-like, or cannabis-like effects or is convertible into a scheduled substance having such effects. If so, the Committee then determines if the substance is liable to similar abuse and produces similar ill effects to the substances in Schedule I or Schedule II, or confirms that it is convertible into a substance already in one of these Schedules.

However, no specific guidance is given in the Guidelines as to how similar to the original drug a substance must be for it to be considered as morphine-like, cocaine-like or cannabis-like. The lack of specific guidance on this matter poses considerable difficulty for the Committee when the drug under review has some similarity for example to both a narcotic drug and a psychotropic substance, because the scheduling criteria in the 1971 Convention on Psychotropic Substances (3) (hereinafter referred to as “the 1971 Convention”) also includes a similarity rule. The decision as to whether to control analgesic and stimulant drugs under the 1961 or 1971 Convention is a major problem. Most potent analgesics are controlled under the 1961 Convention, but a few are controlled as psychotropic substances under the 1971 Convention. Of the stimulants of the central nervous system, cocaine is under the 1961 Convention, whereas amphetamines are under the 1971 Convention. Thus, the criteria for choosing between the two Conventions are ambiguous for these classes of drug.

There are two levels of scheduling criteria for psychotropic substances. At the first level, in addition to similarity to scheduled substances, dependence liability, together with psychotropic effects is an optional criterion. In applying this criterion, it is necessary to confirm that the substance in question has dependence liability and can produce “central nervous system stimulation or depression, resulting in hallucinations or disturbances in motor function, thinking, behaviour, perception or mood”. This criterion has enabled the scheduling of new types of dependence-producing psychotropic substances that are not similar to substances already scheduled. However, the scheduling criteria for psychotropic substances, unlike those for narcotic drugs, have an additional requirement for “evidence that the substance is being or is likely to be abused so as to constitute a significant public health and social problem warranting the placing of the substance under international control”. This provision has deterred this Committee from proposing “preventive” controls for psychotropic substances.

Further details of the scheduling criteria in the 1961 Convention concern the scheduling of:

- preparations of narcotic drugs that can be exempted from certain control measures, such as prescription requirements, (Schedule III); and

- narcotic drugs that are particularly liable to abuse and are replaceable for medical use (Schedule IV).

Examples of narcotic drugs under the 1961 Convention in these Schedules are:

Schedule I

morphine, hydromorphone

Schedule II

codeine, dextropropoxyphene

Schedule III

codeine tablets containing not more than 100 mg/tablet or a cough syrup containing not more than 2.5% codeine

Schedule IV

heroin, cannabis

The Guidelines also provide guidance for selecting an appropriate schedule for psychotropic substances under the 1971 Convention, as follows:

Schedule I

Substances whose liability to abuse constitutes an especially serious risk to public health and which have very limited, if any, therapeutic usefulness.

Schedule II

Substances whose liability to abuse constitutes a substantial risk to public health and which have little to moderate therapeutic usefulness.

Schedule III

Substances whose liability to abuse constitutes a substantial risk to public health and which have moderate to great therapeutic usefulness.

Schedule IV

Substances whose liability to abuse constitutes a smaller but still significant risk to public health and which have a therapeutic usefulness from little to great.

In cases where the above criteria apply only in part, the scheduling recommendation should be made with a higher regard to the risk to public health than to therapeutic usefulness.

Notwithstanding the above, recommendations for inclusion in Schedule I should be made only when the above criteria are fully met, with respect to both therapeutic usefulness and the risk to public health.

Examples of psychotropic substances in these Schedules under the 1971 Convention are:

Schedule I

lysergide (LSD), N,α-dimethyl-3,4-(methlenedioxy) phenethylamine (MDMA)

Schedule II

amphetamines, methaqualone

Schedule III

amobarbital, flunitrazepam, buprenorphine, pentazo cine

Schedule IV

diazepam, amfepramone

It should be noted that the ordering of the Schedules in the two Conventions is not comparable. In the 1961 Convention, Schedule IV is the most restrictive whereas it is the least restrictive in the 1971 Convention. Further confusion may be created by national regulatory systems that use their own scheduling systems.

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