Prehistoric High Times: Early Humans Used Magic Mushrooms, Opium
livescience.com
livescience.com
More seriously, a lot of the conversation around drugs assumed that drugs (from which alcohol is inconsistently excluded) are an unnatural and uncontrollable modern disease. This is also the perspective that predominates in political discussion. The understanding that the low level of drug use "accepted" by modern society is as much a cultural construct as higher levels in the past would go a long way into making our drug policy more sane.
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Strangely, I saw a program on those Irish sites just yesterday spanning from Sligo https://en.wikipedia.org/wiki/County_Sligo#History in the west to Meath https://en.wikipedia.org/wiki/County_Meath#Places_of_interes... in the east which seemed to be implying that the circles represented a religious movement that was pan-European and demonstrably encompassed at least north-western France, Ireland, and northern Scotland. They also divided it in to two periods, an earlier 'earth worship' phase and a later 'sky worship' phase, though much of the interpretation seemed to be pretty close to pure conjecture, they did identify advances in astronomy may have enabled superior navigation leading to technology exchange, seasonal migration, better timed fishing expeditions and wealth from trade. The program also featured a single glyph inside a monolithic grave. Clearly there was some form of pictographic script coming in to use at the time.
It's quite possible that wheat was originally harvested not to make bread but to get people high. There are scientific papers on the psychoactive effects of Triticum.