Cannabis and Cannabis Resin

Pre-Review Report
H. Valerie Curran, Philip Wiffen, David J. Nutt & Willem Scholten
October 2016

The scheduling under the Single Convention on Narcotic Drugs assumes a scientific justification. However, cannabis and cannabis resin have never been evaluated by the World Health Organisation (WHO) since it was mandated the review of psychoactive substances in 1948. The last evaluation for the international substance control conventions were therefore when the League of Nations evaluated them in 1924 and 1935. In 80 years since that decision, both the social context of cannabis use and the science of drug dependence have dramatically changed.


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Yet, because there has never been a formal review, both herbal cannabis and cannabis resin continue to remain under the strictest drug control regime possible. As a result, in the absence of a recent scientific assessment, the continued prohibition of cannabis is completely illegitimate even though it may be legal.

With this wide ranging report (discussing topics from its effects on cognition and learning to mental health and therapeutic benefits), DrugScience enhances the ability of the WHO and its Expert Committee on Drug Dependence (ECDD) in fulfilling its international obligations and enables the Expert Committee to arrive at an independent and scientific recommendation whether a Critical Review is warranted or not.

The report does not come to conclusions on scheduling of cannabis in the international drug control conventions, as this is the prerogative of the ECDD.

Committee recommendations are needed on the following topics:

1. Whether a Critical Review should be conducted for reviewing the current scheduling in Schedules I and IV. Each of the following reasons would justify a recommendation for a Critical Review:

a. because WHO has never conducted a Critical Review, meaning that there is no scientific justification for the current scheduling;
b. because the wide-spread medical use, including the use of preparations with a marketing authorization is in contradiction to listing in Schedule IV;
c. because it is not clear whether the dependence-producing properties of cannabis and cannabis resin are between codeine and morphine (justification for Schedule I) or between dextropropoxyphene and codeine (justification for Schedule II) or below those of dextropropoxyphene (justification for not scheduling).

2. On the medical use of cannabis and its preparations (which can include revoking old recommendations by the Committee)

3. On the need of quality control on cannabis and cannabis products for medical and non-medical use.