[ EDIT for the downvoters: this isn't a joke or some snide remark. The lead hypothesis as the basis for the huge spike in violence in various societies, especially among teenagers and young adults, has huge amounts of evidence. Correlation is not causation, but we even have a plausible causal mechanism. ]
https://www.motherjones.com/kevin-drum/2018/02/an-updated-le...
[ EDIT for the downvoters: this isn't a joke or some snide remark. The lead hypothesis as the basis for the huge spike in violence in various societies, especially among teenagers and young adults, has huge amounts of evidence. Correlation is not causation, but we even have a plausible causal mechanism. ]