In an article in Psychology Today, Amy Barnhorst MD states that we are diagnosing incorrectly if we think that the mass shootings are caused by mental illness. Instead, we should be focusing on guns.
In the study of hierarchies, we know that whatever applies to the top group is assumed to apply to everyone. So if angry white men are shooting people they don't know, then they must be mentally ill. But girls and women who are mentally ill aren't doing this, so obviously the mental illness is not the problem.
Angry white men who want to remain on top of their hierarchies are the issue, and they will do whatever it takes to stay there.
https://www.psychologytoday.com/us/blog/in-crisis/201811/hate-is-not-mental-illness?fbclid=IwAR3gGcG5HEpGR12XcCCGta81Fk_69a_sQkhiIHgwP2dz8wHqPfT4si3rsv4