for those of you who speak German I'd like to recommend the book "Die Kindheit ist politisch" (childhood is political) by German psychohistorian Sven Fuchs: https://www.amazon.com/-/de/dp/3868091432/
. He has put much work in examining the childhood of many well known dictators, warlords, terrorists. His ongoing research (and email address) can be found on his blog http://kriegsursachen.blogspot.com
(existing since 2007, i guess) - and that should be readable with automatic translation. Last year he gave also two lectures available on youtube.