My mother had dementia and died at 86 yo. I think it may have started during her late 70s. She was sending money to all sorts of charities and a place that sent her pictures of the president. She was feeding her beloved dog moldy food. She also bought furniture that she couldn't afford and would walk on the street (or entertain visitors) with just her underwear on. . Finally, her money was gone so these places started having her send money through money orders (a guy would come and get the money and then send the money orders-I think he was associated with one of the national delivery services). Finally, one of her kids was there when the guy came to pick up the money and he told us what was going on. We changed her phone number since that was how these people were getting in touch with her, We finally had to put her into a nursing home. She lived a couple of years there. I would stop after work to be sure she was eating since they didn't have enough workers there to feed everyone (and make sure everyone was eating). They would remove all the food after 1/2 hour even if someone was still eating. When I asked why they said it was the rules (something about the food could be dangerous after 1/2 hour). Another thing I noticed about my mother in the early stages was that when she was writing something she often crossed out something and wrote something that was similar but a little different.