In the current material conditions we're in (everything is the same, we're still in hellworld, but the drug laws are the ideal for these conditions)?
In a social democratic state?
In a socialist state?
In FALGSC?
Would the policies actually change at all in any of these?
You could use the seized drugs as part of a detox program. No one should be addicted to drugs that have lethal withdrawals, and if they get that down bad that we're taking their stash, they need some kind of treatment.
Ultimately addiction is a mental health condition and treatment should stay between you and your doctor. The state shouldn't be dictating how you must treat your addiction anymore than it should be dictating how you must treat your depression.