Of course it will not cure everyone's addiction but it can definitely help most people. Not only are you spending free time doing something constructive and healthy, but exercise can greatly improve your body and image, in the best way possible. You can get fresh air in your lungs and you can lose weight. Its great starting a group or going to gym because then you are also being social and for some drug addicts that could be something they're missing out on. I think it is definitely something everyone, must do, not only drug addicts. Some of us do live busy lives with little time but if we re-organize and prioritize, we can improve our bodies and minds through exercise.