how can you tell?

The little things, certain phrases and frames of reference that just don't occur to people outside all this. There are some concepts and specific ideations that are just about exclusive to this kind of experience.

Hell, sometimes it's even in the way someone stands when they're in a crowd. Things they say, the imagery in the music.

I kind of wish I wasn't aware, because I don't like to think about it happening to people I respect... but then again, they wouldn't be where they are, doing what they do, or at least not writing the way they do if they hadn't had something happen.

But it's a terrifying, if powerful moment, when you listen to a song for the first time and get hit with that "...oh my god, someone else understands".

Have at it.