Qualifications
To be a novelist or screenwriter—zippo. You just have to be good. And get a little lucky. But if you're a business writer or are hoping to land a plum journalism job, a college degree is a near-must (source).
Writers often have trouble with egos—just because your high school creative writing teacher told you that you were a diamond in the rough doesn't mean the rest of the industry is going to welcome you with open arms. You've got to be a pretty smart guy or gal to be a successful writer. And the best place to acquire smarts is at college. That's why you see so many nerds with diplomas.