How would one know unless one asked them? And what difference would it make in the long run? Does it matter why they are being an asshole? For me, the reason does not matter.
They are big people, I am handing them a great deal of money to stay back, they can take care of themselves so if they are hurt (which I cannot imagine any of the ones I hired being) or upset in some fashion - my general response would be "not my problem - go hire your own therapist or butch up"