Jeannie53, I too had many problems with Anastrozole! It was the first medication my doctor had me on following surgery and radiation. I had horrible memory problems from it. There is evidence that cognitive function can indeed be affected by lowering estrogen. This issue is still being researched and I don’t know if the studies are conclusive or not. Many women have trouble with scattered thinking during menopause when our estrogen levels naturally lower. Those of us who need to take drugs following breast cancer to lower our estrogen levels also can have that side effect. My doctor switched me to Tomoxifin from Anastrozole and my cognitive function was much better. Unfortunately I had some sort of allergic reaction to the Tomoxifin and broke out in itching hives all over my body! I was miserable, and needed to take cortisone for several days to clear up the hives. My oncologist gave me a break for about 8 weeks from meds. to restart over again with Exemestane. I’ve been on that for a little over a year and it seems to be much better for me. It’s far from perfect, but I can tolerate it.