If we keep our focus on psychedelics, as per the article, then: no, not really. The Netherlands have had OTC, no-questions-asked, fully commoditised psychedelics available for decades.
Some got put back on the ban list in dec 2008, others still available as before. This should offer plenty actual, real world, practical data.
No need to guess or contemplate!
> Maybe we might want to do an experiment in a city somewhere to see, but even then, I feel the results would be highly politicized, as they are with 'harm reduction clinics' ... it's hard to get at the truth of it.
How about an entire country, for over two decades? :)