[cel1ne]

I think it's possible the hyperactive types try to get rid of their inner tension and negative jumpy emotions by moving.

And, I realise I'm leaning myself out of the window here, I think the inattentive type doesn't have the "dopaminergic focus problems" that strong. He zones out because he is repulsed by given tasks for different reasons. That's the insula and emotions of disgust at play there.