This is a very interesting article on how early experiences of bullying can alter the neurobiology of the brain increasing the likelihood for some individuals to then become bullies themselves. At least that is what I gather as I dog paddle in the deep end of dACC, MAOA, DHEA, so on and so forth!
"Bullying changes neurochemical activation, inhibits neural proliferation and causes neuro-structural changes. These changes set a new trajectory of neural functioning and provide the basis for changes in mood, cognition, and behaviors."