Probably not so hard to do: - Personal reports from drug users - since the majority of users are recreative users and not hardcore junkies, and even those are

Probably not so hard to do: - Personal reports from drug users - since the majority of users are recreative users and not hardcore junkies, and even those are just people with various levels of mental issues, I would actually find this reliable. - There are surveys that are taken, at least here in the EU, that track drug usage. - Quality sampling of confiscated drugs - Analysis of medical data (deaths, overdoses,...) - Analysis of police data (crimes related to drug usage) A lot of data out there.