I think the comment above is understated. There is evidence that psychoactive compounds have been used since at least 3000BCE in Mesoamerica. Looking into it it seems lead was first mined around the same time in Greece but the lead sweetener idea wasn't popular until the roman empire. Note that there were reports even back then of health issues associated with the practice.

http://www.sciencedirect.com/science/article/pii/S2173580814...

Do you have any other examples on the thousands of years timescale?