Chess.com forum regular (well, she used to be here all the time anyway) ------ Batgirl -- is an authority on Morphy... she can no doubt tell you three different theories regarding Morphy's mental state, which she feels is most credible, and what objective data there exists in the historical record. So put up the batsignal and hopefully batgirl will weigh in.
It is, as far as I know, "common knowledge" that Morphy went some kind of nuts or was in some way mentally enfeebled in his later years. I'm rather startled to hear that this isn't readily googleable. it's not in the wiki? Really? *edit* wow, I checked the wiki and indeed the legend of crazy morphy is nowhere to be found... just some odd business about him arranging shoes in a semi-circle.
Somewhere I heard or read that Paul Morphy, great American chess player - perhaps the first unofficial world champion of chess, went crazy. But googling it, I can't find anything on this, only that he essentially quit chess and died in his 40's. Why did I hear or read that he went crazy or insane?