This latest discussion pushes a little outside of my knowledge, but what Fran describes in her H sounds a little to me like a peronality issue, which would be a genetic issue. What I wonder is if he has something like Asperger's.
We know a family with a child diagnosed with Asperger's and she is highly sensitive to outside stimuli which can cause her to erupt. Her safe haven is to go into a small, dark place, like a womb, balled up in fetal position. Leave her there for a while and she is fine. ADD is a step down from Asperger's. The two share some common characteristics.
All my comments my comments on this board exclude any consideration for these types of problems since only a quifies doctor can diagnose or threat them.