I just started taking 25mg of Zoloft for anxiety also. I had been taking 1mg of Ativan but it stopped working and I refused to increase the dosage. At first, Dr. prescribed the Zoloft and .5mg of Ativan IF NEEDED. The first week I had to take the Ativan a few times to calm the anxiety. As weeks went on I totally forgot about the Ativan. The anxiety just began to disappear. I am stunned. I resisted the Zoloft as I had a bad experience with antidepressants many years ago. But Dr. was right, it has help so much. I still do not want to have to take it but until I can find the reason for my fainting spells (which is the cause of the high anxiety) I will. I can't say I experience any brain fog from it. At least not yet. But if so I will keep your experience in mind for reference. I too have memory problems, have for couple of years now, but it hasn't gotten worse. Could it be interacting with another of your medicines to cause this? I will be interested in reading other's responses. I too will never increase my dosage of this. If it stops working at the 25mg, I will stop taking it.