The future of international drug control treaties is in doubt because of recent treaty-violating decisions to legalize cannabis use in Canada, the United States and Uruguay. Professor Wayne Hall, whose 2014 review of 20 years of cannabis research made world headlines, thinks so. If decriminalization is the way of the future, Hall advocates a cautious approach to policy reform that would involve trialling and evaluating the effects of incrementally more liberal drug policies. His suggestions, outlined below, are published online today by the scientific journal Addiction.

The international drug control treaties are endorsed by most member states of the United Nations (UN). The treaties prohibit the non-medical use of amphetamines, cannabis, cocaine and heroin. They aim to reduce the harmful use of prohibited drugs and facilitate access to these drugs for medical and scientific purposes. Critics claim that the treaties have failed to tackle non-medical use of prohibited drugs and have justified policies that conflict with UN human rights treaties by incarcerating large numbers of drug users.

Hall's paper outlines types of policies that nations could adopt to address the different types of harm that different illicit drugs cause to users and others. Some would require treaty change, while others could be accomplished by more 'flexible interpretations' of treaty provisions by member states and UN agencies. His suggestions are: