Anecdotally, I felt the meds that I got during the shortage 6 or so months ago weren’t as effective.
I think they do degrade, but I have no sources. I think I asked my psychiatrist at one point and he said that it usually isn’t a concern.
I’m taking concerta, not Adderall, if that makes a difference.
I don’t think that’s how it works, but I’m too American to be certain.