I hate to jump in on this one, and I am never one to go against anything Hat has to say, however, from the research that I have carried out following my father's diagnosis of Parkinson's and speaking with the UCL where my father volunteers (UKPDC), I would say there is a very strong argument that my father's 20 years on AD's caused his condition.
But... you need to bear in mind his age when he was taking it, and the brains degradation of neuroplasticity capabilities.
At your age AJ, I would certainly say there is very little to be worried about. But I for sure wouldn't stay on them any longer than is needed.