Jail Time is in essence rehab without the professional helthia - wellbeing and unrestrict to unsupervised visits, access to learning etc, should be a part of every rehabilitation/Incarceration centre, be it the first step and last for a drug user or a statuatory release programme for prisoners.
Norway relies on a "restorative justice" system which aims to repair the harm caused by crime rather than punish people. Drugs are not that accessible, I speak from experience.
Drug addiction is not a crime, punishing an addict is.
I took the time to talk to inmates and hear their stories. Every ones got a story, listen carefully and you may find empathy in the strangest of places and if not at least an understanding.