That's all interesting, George, but while you're fishing around in the dustbins of pharmacology, don't forget that there are two things going on today that play into the desires of people suffering from some kinds of mental illnesses and distress: First, if you really need attention (and many of them do), we have cable news and the Internet, by which your glorious revenge will be played around the world in a couple of hours; second, we have tools available today that can really make a big splash.
A hundred years ago, your military Trapdoor Springfield wasn't going to do the job that you can do today with a Bushmaster M4 look-alike. And the news wasn't likely to get past your county line.
It's a qualitatively different situation, and it doesn't require pharmacology to explain it.