My anxiety skyrockets and my depression goes up. There is no way in heck I could even consider quitting while manic and the anxiety and depression are what always force me back to it when I quit. So yeah, I'd say it's a thing. Smoking is a coping mechanism for me so it makes sense if I see it in those simple terms. I've heard it stated that you need to replace it with a positive coping mechanism for the best chance at making it stick.