If you decide to app her as an AU version, we actually have an app for OCs and AUs that is slightly longer than the one for canon characters, and asks for more information about your character headcanon. You can see the template on our how to app page. So you could absolutely use that to describe the ADHD theory in whatever detail you like. :)

There are a small number of counselors on the Enterprise whom Ed could always interact with, if it came up that you would like her ADHD to be diagnosed and publicly recognized IC. That is, of course, entirely up to you, though.