What should we do about cannabis?
No serious commentator doubts that cannabis is potentially damaging to the user. Like tobacco, it is typically smoked and thus shares the potential for lung disease. Like alcohol, it affects reaction times and may raise the risk of road accidents. Cannabis has also been associated with cognitive impairment, deterioration in education performance (van Ours and Williams 2008), and psychotic illness (Arsenault 2004). Moreover, cannabis is often – albeit contentiously – seen as a causal gateway to more serious drug use (Kandel 2002). The question is what to do about it?
The disappointing conclusion – which contrasts with the apparent certainty displayed by some commentators – is that the available evidence is too weak for us to be at all certain about the consequences of radical policy change, as Kilmer et al. (2010) have shown for the legalisation proposals currently under consideration in California. But it is certainly reasonable to entertain the possibility that a legalised, carefully regulated cannabis market could produce better social outcomes than our present system of half-hearted, partially-effective prohibition.
In my view, the best way to begin putting policy on a better footing is to allow more variation in policymaking, including the legalisation option. This could be done if domestic supply and consumption of cannabis were removed from the international drug prohibition treaties, while retaining the ban on international trade in the drug. At present we are limited to decriminalisation unaccompanied by the instruments of regulation available for legal markets, so that the potential benefits of a non-prohibitionist approach are largely precluded. The removal of cannabis from the UN treaty structure would pass the responsibility for cannabis policy back to national governments, with freedom of action to pursue independent policies. Some will choose to stick to the status quo, others will choose decriminalisation or legalisation. In doing so, we will certainly have the chance to learn more about the effects of policy.
November 9, 2010
Centre for Economic Policy Research