I was having this problem too, but I never figured out whether the IBS caused the panic or the panic triggered the attacks...They're definitely connected (check out some of the studies Heather's posted on the Brain-Gut section of the IBS Research Library). I read that panic attacks only last a few minutes and you can have many in a row, but I swear I've had days, weeks, where I felt I was in one on-going panic attack and I couldn't get out of it. In those instances where I couldn't regain control, certain meds, like benzodiazepenes, helped me out. I sort of think of it like a reset button for my brain (I do use them sparingly/only as needed since they're addictive and I don't like the "hangover" effect). For GAD, I take Buspar daily and I believe this has not only helped with my ongoing anxiety but it's also had a good effect on my IBS symptoms as well.