Interesting article Reignette. Thanks for posting. My grandmother ended up with dementia caused by pernicious anemia which was diagnosed too late. She was born in Italy. She started showing signs of dementia in her late 50s but none of her symptoms were anything like those described for Mary Lincoln. Just a comment since a sample of one isn't very scientific.
There sure has been a lot written about Mary Lincoln's health. For example, another doctor, Norbert Hirschhorn, wrote that Mary suffered from tabes dorsalis. Who knows...