By Society for the Study of Addiction

The level of drug use in the population is an ongoing topic of conern for policymakers, and regular adjustments to the penalty for this might reflect how much sanctions are viewed politically as appropriate to deter use. It is therefore interesting that noy only it is difficult to observe the impact of such adjustments on cannabias prevalence, but also policymakers addressing new challenges do not always penalize use of personal posssession.
 
Article 3(2) of the United Nations Convention on illicit trafficing requests (although does not oblige) states to criminalize possesion of drugs for personal use. increasing statutory penalty has been presented as a measure to reduce use, assuming that increasing penalties deters drug usage, adn reducing them increases it.