I never took Topamax, but definitely heard and read about the issue you described with it. And its "Dopamax" nickname. I think other anticonvulsant moodstabilizers can have a similar side effect, although usually milder. I agree that dose can affect the severity. When I took higher doses of Lamictal I had cognitive dulling (including word retrieval difficulties) but at my lower dose it's barely an issue. I used to take quite high doses of Tegretol, too. Tegretol didn't affect me cognitively as much as with balance and similar issues. At my lower doses, even these side effects are minimal. They all usually have some effects beyond what they're meant to. High doses of Depakote gave me balance issues, too.