Are there any AA or NA meetings near you?
As you bought it up you will maybe have thought about this too...the drugs, drink, whatever are the full stop to the sentence...you use them because of you so you will need to change so that you dont need to use the crutches anymore...
AA helped me to deal with the sentence so with a different sentence now no need for the full stop, life can be a journey and an adventure not just serving time...