Only one country in history has ever successfully made a significant reduction in drug addiction. In fact they achieved more than a 90% drop in heroine addiction. And they did it by doing the one thing no other country has had the courage to do: decriminalizing all drugs and treating addiction as a public health problem, not a crime.
In Portugal if you're caught with heroine (or any other illegal drug), you are paid a visit - not by the police but by a social worker. The social worker will run you through a questionaire to guage your level of use and risk factors. Then - reccomend a (completely free and completely voluntary) treatment program - which you may make use of if you are so inclined.
The free treatment programs are of the class of top private institutions - fully funded by money saved on trying to police the unpoliceable, attendence is truly voluntary, nobody *has* to go -but everybody who wants to, can.

We should copy that program. It's the only one in history that worked.