Re Q crumbs. Not sure if already posted.
"The overwhelming evidence points to the signal largest common factor in all of these incidents is the fact that all of the perpetrators were either actively taking powerful psychotropic drugs or had been at some point in the immediate past before they committed their crimes."
Sauce:
https:// ammoland.com/2013/04/every-mass-shooting-in-the-last-20-years-shares-psychotropic-drugs/