I took it for about 4 years too and same thing. I remember there was a huge lag in thinking what I wanted to say and actually saying it - so I seemed quite slow in actual conversation. I appeared very socially awkward, and it made me withdrawn, however I did not know this at the time. I had to go IP for an eating disorder, depression, anxiety, general breakdown, and my meds were completely overhauled, and I finally realized the topamax was the cause behind my brain fog. I wasn’t stuttering or grasping for words anymore, I could keep up with conversation, even make people laugh. Ironically, I’m now back on it bc it works for me as a mood stabilizer, somewhat. The second time you take it, it is less effective and the side effects are so much less compared to the first time (no tingles, zero appetite suppression, so far cognition okay) and it’s been maybe 6 or 8 months on 250mg. If I start getting dopey again, it will be time to come off of it though.