I know he has hinted (stated?) that cycling kept him from an otherwise unsavoury lifestyle... (who said cycling was 'savoury'!!)
But, and forgive my breathtaking cynicism here, could this not just be convenient back story? A lot of people come with baggage of one type or another, we just don't always hear about it because they deal with it or channel it. I don't mean to be unsympathetic but couldn't Cavendish's problems by more simplistic?
I know it might sound flippant, but can he actually sprint in a straight line!
Seriously, maybe there's a problem with technique or approach at the moment. Maybe he's having problems, getting frustrated with them and boiling over? What I do know, and sympathise with, is that it's not been a good year for him so far, that's for real.