Distinguishing personal use of drugs from drug supply: Approaches and challenges.

The ability to fairly and justly distinguish between drug possession for personal use and drug possession for supply is a central feature of drug laws across the globe. Whether such distinctions pertain to decriminalisation of simple possession, or to the penalties associated with drug offences, such differentiation remains a core problem for policymakers. In this commentary, taking 91 different jurisdictions into consideration, we identify five different approaches to distinguishing personal use from supply: four of these involved quantification of an amount of drug (whether in weight or number of doses).