This is a social issue, not a criminal. Stop wasting criminal justice resources on prohibition.
Prohibition of cannabis does not work. It is very expensive way to "regulate" its use, and serves only on purpose: to suppot the black economy with all the links to organised crime and hard drugs.
Prohibition does nothing to stop demand. Let's start by taking a common sense approach and have a rational and informed debate about drug use in our society.
Want to save the state money? End prohibition.