Might be, but it is ALL, 100%, self-induced. I don't mean you caused the stressful circumstance, I mean that only YOU can permit the a bad circumstance to be internalized as stress. It would seem like the only disease where your mind-set can control whether or not you get it.
Stressful situations and humor:
About 13 years ago my wife and I were on a TACA Airlines 737 flying around Central America. Through ignorance and incompetence the pilot took the plane within one or two seconds of eating the wrong end of a box canyon deep in the Guatemalan jungles. When my wife saw what almost happened she turned to me calmly and said: Wow, we darn near lost our frequent flyer miles there".
Short of loosing a loved one, there is no situation so serious that you can't make it better by finding the light side and laughing at it. Life doesn't get worth living until you look the grim reaper dead in the eye and make a wise crack about who the hell his tailor is.
There is a trick to learning how to do that. Think of some famous deadly event, you know, like the sinking of the Titanic or the crash of the shuttle Challenger. Imagine yourself on board and you turn to the captain and quip....what?...Hey, Captain, you know the last thing that going to go through your mind? A halibut! (drum roll) Now your turn. Try it.
--Boot Hill
You are correct, of course. This has been the only way I have survived thus far.
There ARE, however, limits to this strategy.
At some point you must radically CHANGE the stress-causing situation. This, I am in the process of doing.
If you are unable to make an unworkable situation workable - after giving it the utmost of your patience, resources and endurance - then ya gotta change the situation. Period.