[TheHypnotist]

The problem is not using drugs. The problem is committing crimes while using drugs. Some people can use drugs and avoid crime. Others use drugs and commit crime.

You forgot those who commit crimes in an effort to use drugs. I think treatment inside jail (or some controlled environment) is probably your best bet. If you have someone who's addiction is clouding their judgement, they might say anything just to stay out of jail, but how do you get them to follow through?