I think it's common in people who have preoblems with stress and anxiety, and people with AS are prone to those things so probably. But it's also common in normal people too.
I have IBS, and for me it means lots of erratic bowel movements and needing to go toilet a lot even if there's nothing there. And I sometimes get pains and stuff if it's bad enough, I usually get the symptoms in the morning. It tends to get worse when I have to go out somewhere, in the summer holidays my IBS rarely flarred up because I could relax at home, but on the day I went on a day trip I had really loose poo in the morning. So for me it's psychological mostly, I know I'm going out so my IBS starts up.
Is that the kind of information you were looking for?
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What film do atheists watch on Christmas?
Coincidence on 34th street.