But very few drugs cause damage to other people, excluding distribution-related violence. Really there's just the trio of opiates, meth and cocaine that lead to

But very few drugs cause damage to other people, excluding distribution-related violence. Really there's just the trio of opiates, meth and cocaine that lead to real social problems of people commiting crimes while on/obtaining drugs. But, then, there's the point: if your drug use is hurting other people, your actions are already a crime. It can be useful, sometimes, to criminalize a harmless behavior that usually leads to harmful behavior if it would be impractical to enforce laws agains the harmful behavior. But its much easier to enforce laws against theft or starting fights than against possession of small quantities of a substance. Apart from those outliers I listed above, the only common negative result to people other than the user is their lack of productivity and the economic implications of that. And even of those outliers, most users are not addicts and do not hurt others with their drug use.