"Omega-3's foster the growth of neurons in the brain's frontal 
cortex, the bit of gray matter that controls impulsive behavior. 
Having enough of these fatty acids may keep violent impulses in check. "

http://www.freakonomics.com/blog/2006/04/17/you-are-hereby-sentenced-to-5-years-of-salmon-steaks/

www.peoplewho.org