I took ritalin/concerta for many years and was prompted to discontinue using it by my doctor who emphasized how much stress it puts on your system.
When I stopped using it, I had to relearn my methods of memorization. Instead of rote memory, I had to use routines and such to form basic short term memories, but I can say I am fairly well adjusted now and I am trying to get my younger brother to also stop using Concerta for the same reasons.