I suspect it's partly diagnostic creep. Either real actual professional creep, or self diagnosis.

Some mental illnessess are extreme versions of traits that are often useful. It's good have one person in the village who frets about dangerous stuff, for example. Anxiety is useful at times.

But as you start to diagnose the very functional people who just need a few points to get a top uni course (or people self diagnose) ... well ... maybe you're picking up far less extreme and maladaptive versions of the trait.