I am going to share my experience of this because I don't think the general public are often made aware that for some people, meditation can trigger more anxiety rather than reduce it.
I was part of a Uni's Mindfulness research participation group, instructed by the Psychology professor on how to practice mindfulness meditation daily, periodically had them put electrodes on a skull cap on my head, did computer testing, the whole lot.
Then halfway through the stint (it was supposed to take about six months in total I think), I developed my first full-blown panic attack one weekday night, unexpectedly - and it was after I had practised a session of the Mindfulness meditation I was instructed to perform on a daily basis. It was dead scary for me, I had no idea what it was at the time, all I knew was I just had this sensation of andrenaline racing up and down my spine constantly and my heart was pounding and everytime I dozed off in bed I would be startled awake with loud clap sounds that were all in my head because no one else heard then (I later found out these were auditory hallucinations triggered by anxiety). I basically could not sleep at all like that, for 2 whole weeks. I was a total wreck, struggled to cope daily, friend and husband helped me out with the school runs.
All the while I was feeling so exasperated because I just did not know what was wrong with me, and the doctors I saw couldn't tell me why this just came about either, all they did was run loads of tests on my blood, heart, lungs, thyroid, found everythinh was normal. Eventually I was told this was probably anxiety related even though I had not been going through any stressful situation back then which could have caused it.
I was put on Citalopram which to be honest did nothing noticeable for my anxiety. However I was very lucky. I had an ACT (Acceptance and Commitment thetapy) workbook lying around at home which I bought ages ago to try and self treat my phobias. I made myself do all the mental exercises in it and it actually helped a lot. I've always had underlying anxiety but never became full blown panic attacks. I came across this article about a year after that, and it seemed to explain somewhat the reasons behind what happened to me. www.slate.com/articles/arts/culturebox/2003/02/buddhist_retreat.html Looking back, I think the Mindfulness exercises I did before my first full blown attack sort of brought it all out to the fore. Provoked more anxiety, paradoxically.
Funny enough, ACT really seems to be an offshoot of Mindfulness practice. But it's quite different from what I was instructed with by the Uni prof during the study in that it is more than just sitting there quietly being aware of one's feelings. It just helped me deal with my panic attacks and anxiety much more effectively. I stopped the Citalopram after a month because it was giving me horrible gastric problems, but found I didn't need it anymore by just using the ACT techniques.
I would personally recommend ACT for anxiety myself. I tried to find an ACT practitioner in my area but could not find one. Apparently its a newer treatment than CBT so only in America is it more known... In England not so many would do it. But I feel right now, a practitioner would be a plus but not absolutely necessary. It's been a while since I've had any more panic attacks. And I still am not sure entirely why ACT techniques worked for me but the Mindfulness meditation I was taught did not...
I am aware that I might be sort of the odd one out for saying this. Meditation is good for many people. Just unfortunately I suffered bad results from one form of it.