Yes, what you wrote about PTSD, anti-depressants is true. And recent prescribed anti-depressants is true re the Vegas shooter as well btw.  It was the first thing that came to mind when i read it. I second this:  PTSD and depression should be reasons not to be allowed to possess a gun.

"Drug given to Paddock calms some, provokes others, experts say"
https://www.reviewjournal.com/local/the-strip/drug-given-to-paddock-calms-some-provokes-others-experts-say/