If you read through the many success stories from the members of the nomorepanic forum you will see that CBT4PANIC worked for them remarkably quickly.
Obviously everyone takes things in in different ways but really you should see progress right from the start because the problem is to do with misinterpreting harmless yet frightening symptoms of fight or flight. so once you really understand this at a deep level and start understanding how to correct that mistake you HAVE to improve.
Imagine that you had thought for years that 2 + 2 = 5
Once you are shown WHY the correct answer is ‘4’ you can’t really go back to thinking the answer is ‘5’ again
It’s the same with Panic attacks. Once you really understand WHY you have been perpetuating the problem through your own mistaken thoughts and reactions then once you start correcting those mistakes you will see results very quickly