i don't think there's reason to go for the conspiracy here. Firstly, the effect of drug use in indigenous cultures may be limited (strongly) by culture: smalle

i don't think there's reason to go for the conspiracy here. Firstly, the effect of drug use in indigenous cultures may be limited (strongly) by culture: smaller communities having much stronger social controls on individuals' behaviour, which may in practice result in rules for drug use (and consequences for misuse) much like our's, just not in writing. Secondly, there seems to be a mechanism by which a culture develops shared methods to handle drugs by various means. See for example the difficulty indigenous cultures have had again and again in adapting to alcohol – compared to western cultures' relative benign[0] relationship with alcohol. Even within western cultures, there are differences in adaptation, with good adaptation usually being anti correlated to level of regulation. From the jewish and southern European cultures where 8-year old get a glass of red wine with lunch to the inebriated inanity that is the UK at last call. [0]: "relative" being the operative word here – alcohol obviously is a huge burden on western societies, in direct health effects, domestic violence, traffic deaths etc.