I'm not sure I've been "officially diagnosed" with panic disorder. I had lots of stomach problems for a long time and eventually broke down and took myself to a hospital. There, I saw an Internist in the "Center for Diagnostic Medicine". He ran tons and tons of blood work on my and referred me to one of the hospital's gastroenterologists. He ran a bunch of tests on me and found nothing. On my last visit he mentioned "atypical panic attacks" and ordered a couple more stomach tests to rule things out. Those were somewhat invasive so I canceled them and went back to the first doctor. I told him that it took me about a week to get a grip on the anxiety/panic thing and then I actually started feeling better. He agreed that that's probably what it was, and in spite of skipping the last two tests said I'd had a very comprehensive GI workup. Agreed that it was probably anxiety/panic and discharged me with no medical help. He said my stomach would feel better as my anxiety got better, and my anxiety would get better as my stomach got better. That made little sense to me but I didn't care much since I wasn't feeling bad at the time.
Eventually I started suffering the attacks again, though. They actually never stopped...just decreased in intensity, frequency, and duration...but they still happened. After some time they got as bad as they ever were and I decided I needed medicine to deal with it. No relaxation methods were working. So I went to my family doctor here in town and he mentioned three possibilities: IBS, Abdominal Migraines, and Anxiety/Panic. Since the other two docs agreed on panic, he decided to treat me for that first and gave me Clonazepam.
Afraid of pills, it literally took weeks before I was able to try the meds. When I did, though, I made an immediate turn around and have been doing better ever since. I'm still not perfect, but I'm much better than I've been in a very long time.
So that pretty much confirmed the diagnosis. I have GERD and Anxiety. Each condition is aggravated by the other, just like the internist at the hospital said. When the anxiety improved, the GERD got a lot better, too.
So that's that, pretty much. I've never seen a psychiatrist for this.