There have been studies with chimpanzee colonies that showed that the larger the group the more violent the chimpanzees would become with one another…I'm going against the flow here and say I think the information presented is worthy of consideration. Because I'd like to know why this form of violence is happening with greater frequency when it didn't occur much in the past. Why the increase? Are there more mentally ill people about? If so, why? I've got my own views as to why. For example, people are living in ever more crowded-up environments, frustrations with their fellow man are more frequent. Life in general is more regulated. I also think there is some monkey-see, monkey-do factor due to the increased reach of media coverage.
Some countries do require a psych exam or interview before a firearm purchase permit is issued. As much of a hindrance I think this might be, I'm also aware that changes in society might move us toward that. We all know or have met gun owners whom we've thought maybe ought not to have them. I doubt that the Founding Fathers would've wanted the village idiot to have a musket.