Let's pretend that you have a childhood disorder that gets a lot of media attention and a lot of funding. You also have a caring and conscientious pediatrician who understands that his patients need more help than funding will allow. So he labels them with this new politically fueled diagnosis to be sure they get the help they need.
This, in turn, inflates the number of children diagnosed and encourages the concept of an "epidemic".
In reality, it is just the result of politics and medicine and people doing their best to get remedial help paid for so that children stand a chance of getting ahead in life.
But, you know, epidemic is fun to say. And it causes panic. And this increases funding. So let's just increase the parameters of the disorder and start diagnosing everyone with it.