Now that is quite the switch of topic. The only known research of race differences in psychopathy is of Richard Lynn's 2002 studies on the topic. In this, Lynn does point to whites being more prone to psychosis than on average. I do know of some controversy of Richard Lynn's work, and here is a response paper to such: https://web.archive.org/web/20130108233748/http://riskreduct...

Regarding school shootings in particular, my personal guess is that such sour actions on the average are merely a symptom of a hole in America's conscious, in that these semi-affluent white boys have lost meaning in life, and do not care if the actions they commit are grave. Of particular note is you do not see boys of abject poverty commit these actions, as they are more focused on not starving (and thus have something obviously meaningful to their life to prioritize).