I had test anxiety so bad that the morning of an exam, I'd wake up in extreme pain from my stomach, and diarrhea, and the intense, intense pain (worst of my life, and I've had a lot of bad things in my life) wouldn't let up until a few hours after the exam, and I'd have to run to the washroom cuz of the diarrhea like for half an hour out of every 3 hour exam, and the night before the exam I'd sleep maybe an hour, I'd try to drink to get to sleep but that wouldn't help, either -- I'd be stumbling the morning of the exam, not able to even walk properly because of it --
so now I have sedatives so that I can sleep and not have such severe stomach cramps. If you're in a situation like mine, I highly recommend them. They're not good for long-term use (at least, mine aren't), but for exams, damn.
Of course, they *are* sedatives. But if it's between that and being in extreme pain during an exam and missing half an hour out of every 3 hr exam to go to the washroom and get only an hour of sleep the night before, I'd rather have my brain on sedatives.
I don't have any other anxiety problem, it's Only with exams.
And whoever says it has anything to do with being comfortable with the material, you're dead wrong. It doesn't matter if I know the stuff thoroughly. Because you can know it inside-out and still worry.