I had the very same thing happen to me, including some permanent memory loss, and that was at age 27!

But my retardation wasn't because of untreated bipolar, it was actually the exact opposite.

2 years after quitting my dumbing down drugs I have improved quite substantially. The only issue I'm still working on is word recognition,but I'm back to being a bookworm, which helps immensely!

A few members here have mentioned playing brain teazer type games to exercise their noodles, memory games come to mind first.

Uhm, I don't actually have a solution for you, but I do know what its like to feel your once brilliant brain rot inside your head, and the subsequent self-esteem blows that follow.