Mechanisms to enforce medication usage in the community do exist, usually by in-person visits to supervise taking medication. One such program is the "Assertive Community Treatment" model that exists in a couple different places in the US, here's a report from the King County (WA) group: http://www.kingcounty.gov/~/media/health/mentalHealth/Docume...

I think the actual 'enforcement' in the way you are thinking would be backed up with some kind of court ruling that they were required to take the medication, I'm not so sure how that angle would work.