can also cause some of these issues. My son was diagnosed when he was in first grade. There is lots on the internet about it. Kids with this cannot process all the sensory information coming in at them and it makes them anxious. My son used to like to spin on the ground like a break dancer because it got his nervous system going. It seems to be prevalent in smart kids because their brains are taking in more information, but their nervous system cannot process it quickly enough.