Evidently, crazy people with syphilis develop these tertiary lues, a visual clue to the root cause of schizophrenic behaviors.

In WWII, Syphilis and gonorrhea was a major concern, and I love the old WWII VD posters:

Syphilis was one rare, but this fatal form of crotch rot is making a comeback:

So what do tertiary lues look like?
Click the link for an image search for tertiary lues if you dare . . . .