I have a foster with the same condition. Stress can bring it on; she had been bouncing from foster home to foster home. I had her on Cosequin for awhile; now she's not on everything and thriving. But, every cat is different.

I think the best barometer for a cat's well-being is: how well is he/she eating? That has been a solid indicator for my cats; which have had a wide range of health issues. If Irwin is eating, drinking, and doesn't have major behavioral changes, I would say just manage his condition as best you can. Good luck and give him a scritch for me, please.