Back in the 70s, Isaac Asimov (SF writer who'd won a number of awards) taught a class at Boston College. My GF of the time was in that class. I was an Asimov fan, got to sit in on a few (but only a few as I was in the hotel biz so not much free time).

He described writing as 'an affliction that only putting words to page can assuage' (not his exact words but, hey, that was nearly 50 years ago and I wasn't taking notes). I've read that Stephen King (another prolific writer) had described it in a similar way.