> Drug use goes back as far as humankind does because people have been trying to cope with the stress of life since there have been people.
I do not think the second half of your statement is true. Certainly there was drug use in hunter/gatherer societies but it was mostly shamanistic/ritualistic use, not 'stress relief'. The example that you give of alcohol only really came on the scene with the advent of farming, which remains a small fraction of the history of humankind.
Ok, I just did a bit of searching for studies on hunter-gatherer use of drugs.
This paper [1] supports my characterisation of being mostly for shamanistic/ritualistic use.
And this paper [2] suggests that drug use also had medicinal benefits. But that is from a modern hunter-gatherer society that has undoubtedly been influenced by outside societies (indeed the drug they smoke has been imported from another continent), so I'm not sure how indicative of pre-historic hunter-gatherer use it is.
Where I remain dubious is the assertion that drugs have always been used for 'stress relief'. My feeling is that stress - as we understand it - was not something much experienced by hunter-gatherer societies.
I do not think the second half of your statement is true. Certainly there was drug use in hunter/gatherer societies but it was mostly shamanistic/ritualistic use, not 'stress relief'. The example that you give of alcohol only really came on the scene with the advent of farming, which remains a small fraction of the history of humankind.