There's a tendency to for diagnoses to double duty, both as description and explanation. Why does he do those things? Because he's autistic. And why do we call him autistic? Because he does those things.

It's especially bad for things which are defined by "at least n of these m things", including depression, addiction, and a ton of other psychological diagnoses. Are we getting any wiser from such definitions at all?

(But there's the issue of insurance, or rationing assistance more generally, which compels us to keep using these non-explaining diagnoses.)