"These kinds of symptoms help explain why national surveys of everyday U.S. gun violence frequently show persons diagnosed with mental illness vastly under-represented as perpetrators when compared with a far more volatile population: the sane."

And here's an idea:

"By 2013, those attitudes had shifted: 48 percent said protection was the main reason to own a gun, while 32 percent pointed to hunting. The question of why Americans feel so unsafe around, and mistrustful of each other seems like a pressing one for mental health experts."

Maybe buying multiple high-capacity guns and citing the need for protection should be diagnosed as paranoid delusion, which actually *is* predictive of gun violence.