I wouldn't say he was a nut-case, but certainly there's a serious character flaw which shows up dramatically in the heat of a match. If we were to use something like Transactional Analysis, then Suarez somehow slips into a child state during the moment of extreme emotion for him, and reacts purely as an irrational child. To the onlooker, he was just beaten to the ball, to him, at that moment, it was like the world had caved in. Parents of certain young children will recognise the behavioural pattern. I'm not at all certain that he can control his trait and, in my opinion, it would be difficult to coach that kind of behaviour out of his personality. Nut-case, no. Loose cannon, yes in my opinion.
I'd like to read the thoughts of any psychology students or professionals who might frequent the forum.