that... doesn't really matter? using it as an insult in general is harmful. and as I said, people with ADHD can't reclaim this particular slur. why would you even want to use it in the first place? it's just rude and inconsiderate.
adhd isn't a form of mental slowness. adhd is a difference in the way we see the world, not a difference in brain growth. it doesn't matter if you don't see it as a slur, people use it as a slur regardless. it's harmful to a lot of people to disregard a word blatantly used to insult mentally ill people. hope this helps <3