I've only been on Lamictal for about 7 weeks an YES it diminishes the memory!! I too have always been great with numbers, dates and using big words (my Boyfriend hates that last part) but now I can hardly get out a full sentence with just a few simple words. Just today I was making arrangements to eat lunch with my youngest son (2nd grader ) and as I was asking the secretary about it she had to tell ME what I was asking! Grrrr very frustrated!!