No you don't out grow it. My husband was diagnosed with ADHD when he was a child. his parents were told that he would out grow it so as he got older they paid less and less attention to his ADHD. At the age of 27 he was re-diagnosed and put back on meds.

I personally belive that if his treatment wasn't stopped in his teens he would be in a much better place right now. He would know how to cope and deal with his ADHD much better.