You don't just need to have a "sane policy".

You need to have a sane culture.

For one, a culture that doesn't treat alcohol as something necessary for having fun (e.g binge drinking on weekends, etc), but as something social you can have while eating with friends, etc.

Second, a culture (society) that doesn't cripple people, produce mass stress and depression, etc so that they take it to alcohol and drugs.

As long as you don't have those, there will always be people taking it to alcoholism. Heck, even with those you'll still have some people (but much less). But then again people can destroy themselves in 200 other ways too, if they are so inclined (from over- and under-eating to straight suicide).