Geodon helped me the most in terms of squashing that hypervigilance/exaggerated startle response/electric anxiety feeling. I've tried many different drugs over the years, some pre-diagnosis, some post-diagnosis....and while all of the symptoms were PTSD related in one way or another, my body chemistry definitely changed when I went fully symptomatic about 7 years ago.
I also have a prescription for Ativan but I have to be SUPER careful about the dosing as if I take it too often, it brings out anger issues in me. I keep it on hand though because there are times when I truly do need it because I just can't calm down.
But, having said that, I am quite med sensitive and its been hard for me to find meds that help without a lot of unwanted side effects. Everyone is different so unfortunately, after hearing that a medication has helped other people, the only real thing that you can do is try it for yourself.
I was lucky in that there used to be this website called "carrot of hope" which recommended three medications for PTSD, Geodon, Vistaril, and Inderal, and I found it very soon after I was diagnosed when I was looking for meds recommended for PTSD. They called it the "PTSD Cocktail". I was desperate to find something that would give me relief, and Geodon was the drug that calmed me down in the first dose. I think I slept for 18 hours after the first dose! (A welcome relief after hardly sleeping in the previous 2 months.) I've been in and out of the hospital with doctors who have tried to switch up my meds in order to see if something else would work better, but nothing ever has. I have the Geodon on hand for when my symptoms get bad, but fortunately that happens only once or twice a year now. My current doc told me that the symptom relief that I get from the Geodon isn't one of those things where you need to let the drug build up in your system. I've met other people who have been given the drug PRN as well (even though that's a more unusual way to prescribe it).
Geodon is an antipsychotic and not without its share of serious side effects, some of which I have experienced. For this reason, I recommend that others try other classes of medications first such as antidepressants. And, its a huge reason why I don't take it regularly as I know it has a bad effect on my system. (Muscular issues) But, since its the only med that helps me, I sort of have to take that risk when I'm hitting rock bottom and need relief.
I tried Paxil about 20 years ago and it didn't help my depression. I didn't have a high anxiety level to deal with at that point so I can't comment on it helping anxiety. I remember that the dose was pushed higher until I was sleeping all the time and only awake to go to school from 7 to 4. After 2 weeks of that, my parents decided enough was enough and that I shouldn't be on it anymore as I was non-functional. But again, back then I was mainly dealing with depression, not full blown PTSD.
I think I've gone off on a bit of a tangent, but I hope what I've said helps!