Sertraline
"I have suffered from anxiety since I was in my teens, I'm now in my 40's and have GAD.  I first started taking this medicine and it gave me really bad diarrhea and I stopped taking it but it was definitely helping with the panic attacks, I didn't have them at all!  I could feel one like it was about to come on but would go away just as quick.  I stopped taking it because of the diarrhea and tried others like lexapro which didn't do anything at all for me.  I was on 100mg sertraline and talked to my doctor about lowering my dosage to 25mg to start with so I don't experience the side effects so much, I'm up to 50mg now and it's working great."