I've mentioned his issues in a couple of places, but not really in depth I think. We're pretty certain he has sensory processing disorder which, for him, causes major problems with transitions, crowds, new experiences, etc... He has all the normal tantrums a ND kid has plus these mega-tantrums that can last over an hour of inconsolable screaming on a daily basis. He's very social in small groups of people he knows, but can be very physical and aggressive with kids, especially his older brother.
I knew he wasn't ND because he has always been above the curve developmentally, I just wasn't (still don't think I am) ready to actually accept a possible "official" 2e diagnosis. It won't change him at all, but it will be "official"...