Deciding to write a novel about something - as opposed to finding you are writing a novel around something - sounds to me like a good evocation of writer's block.
“Initially with The Butcher Boy, there was this kid growing up in this strange, weird environment that I remember from when I was a kid. And Patrick's vision was so complete there.”
“I did what most writers do when something happens that's overwhelming, fascinating, moving, all of that. I didn't know what else to do about it except write about it.”