This one is very sweet and yes, it shows that it is an oldie. But actually, compared to many other posts at that time this one is at the peak. I would love to see this one shaped up a bit, many nice ideas in the comment section that could easily be implemented into the sub itself. But then again, it is also useful as it is.
A unique city and problem for characters to encounter. It can be a great place for a party to be tasked with infiltrating for the purpose of either retrieving a lost artifact or rescuing someone accidentally sent here. (assuming they aren't already infected by the insanity.)
Another interest possibility is that it's not the people that are insane but more an artifact or curse upon the area that's making them act insane. Trying to smuggle someone out to verify this could prove quite challenging, especially if the persons insanities are disruptive or extremely dangerous.