Oh, crap. The field has a really bad record in childhood mental disorders. (Of course, historically they have a bad record in adult mental disorders, such as considering homosexuality a treatable disorder.) But they took a perfectly good adult diagnosis (bipolar disorder) and applied it to thousands of kids where it was clearly not appropriate if bipolar means the same thing in kids that it does in adults. They took a perfectly good definition of dyslexia and made it into a diagnosis of anyone with a certain reading ability below grade level for whatever reason.
So I predict that if this is put into the DSM, it will be applied to pretty much any kid who throws temper tantrums and whom the evaluator doesn't like. It will be diagnosed earlier and earlier, and some forward-thinking parents will get their normal two-year-olds diagnosed as TDD so they will get extra time on tests in high school and college.