This also happens with ADHD. There are 3 "types" but last I checked, I think there were believed to be 6 distinct disorders or underlying problems under those labels. You could have one or more of them.

Psychology has come a long way in the last few decades but it still has a long way to go.

I'm actually not sure psychology has come a long way in the last decades. There's a ton of research, but almost all of it is simply wrong. Treatment hasn't progressed. The only new, somewhat successful therapy I know of is EMDR, and that's been overblown quite a bit. The rest was already around in the 1990s, and CBT is even older.