So my idea is this: Anybody can do anything they want to themselves. If they harm another in doing it, I mean in an immediate, direct fashion; something as long term and indirect as second hand smoke would not be considered, then they are punished as if they had full control of their mental faculties and acted with malice aforethought.
The government, at any level, could not pay to rehabilitate or give medical assistance for any substance induced harm. They would be on their own to solve their problems, unless family, church, or private organizations stepped in.
I find myself in much the same situation. I like the libertarian ideal of one doing what one pleases as long as that does not harm another, but a necessary part of this is that one must accept the consequences of one’s own freely-chosen actions. If harm to one’s self or to others results from these actions, one should repair the harm using one’s own resources, or those given voluntarily by others.
Unfortunately, in this society, people are not held accountable for their actions, and the government uses the confiscated resources of others to repair harm from such actions. As long as this continues, and I do not look for a change any time soon, libertarianism cannot work.