I remember reading that he used to watch really violent movies and laugh at the murders and such. Also, Steart talked about how he had the run of his house, and used to lock himself in a tiny basement room with a shotgun. Stuff like that.
I always read he was an anti-social guy, I don't know if he had a condition. I can't remember who said it but apparently if he got a blood nose in sparing he liked to go into the showers fully clothed, head gear still on and stand there for a while under running water and all other manner of weird things. My favourite story about Mike was that when he wanted to retire after winning the title to be a cop they refused because he KO'd one.