Thank you for letting me know that can happen. It happened to me. Marti
Anxiety/Panic causes an increase in heart rate and blood pressure. "Passing out" is generally attributed to a sudden drop in blood pressure, so I'm not sure how you could pass out from it. Granted, you can feel like you are going to pass out, or FEAR that you are going to pass out. During my first panic attack I thought I was going to pass out, but that was due to my body going into fight or flight mode and my vision pretty much turning into tunnel vision with just a narrow field of vision. I thought I was blacking out, but I wasn't.
Just yesterday i had a bad panic attack, threw up, and passed out, so yes, it can happen
Yes, from my experience it will cause a lot, upset stomach, inablityto breath and hyperventilate. Also, one day i couldn't get calm enough to find my daughters house, I ended up one street over and she had lived there forever, I had to take something strong at that time.