A few tangential questions: Assuming services are available and accessible on a voluntary basis, what is the success rate for overcoming major substance abuse

A few tangential questions: Assuming services are available and accessible on a voluntary basis, what is the success rate for overcoming major substance abuse or mental health issues? How does that success rate change with various levels of coercion? Assuming the success rate is fairly low, that still leaves a lot of people with substance abuse or mental health problems. What is the right thing to do for them? Independent housing is one option but wouldn't some kind of institution make more sense? If someone's main problem is homelessness and some minor criminal behavior, I can imagine that free housing could turn their situation around quickly. But only if it's a safe environment around similarly-situated people.