Let me start.
There are tools. We call them “readiness to learn”. People will engage in changing their behaviour when they're ready to do it. There are four different ranges that you get, and you have to help people move through those things. You will not move until you're ready, and there is a whole science behind how you do that.
In our prevention and rehab program, we test people. We know where they're at. Sometimes we just say this: “You know what? You're going to have a problem in five years.” That's the best you can do. Sometimes they're much more ready. There are many behavioural change models that are used in different settings, and they work when they're done properly and you understand where people are. It's possible to help people change.