Stephen King has said that if it was not for writing he would have become a mass shooter.

In Stephen King: A Biography, Albert Rolls writes that the story "Cain Rose Up":

" drew its immediate inspiration from the case of Charles Whitman, a former marine and a student at the University of Texas who in 1966 positioned himself within the University of Texas Tower in Austin, the tallest building on the campus, and began shooting people. In King’s tale the Whitman character, Curt Garrish, holes up in his dorm room and kills people with a .357 magnum. The gesture was one with which King himself identified, he would later say. “I might very well have ended up there in the Texas tower with Charlie Whitman, working out my demons with a high-powered telescopic rifle instead of a word processor. I mean, I know that guy Whitman. My writing has kept me out of that tower.”"

Rolls give the source as follows:
Eric Norden, “Playboy Interview,” in Bare Bones: Conversations on Terror with Stephen King, ed. Tim Underwood and Chuck Miller (New York: McGraw-Hill, 1988), p. 44.

Well, I guess that's a reasonable thing to have on your resume if you're a horror writer.

I'm sure the confession didn't carry as much weight back when King admitted it as it would have if he repeated it today.