From a great height

We've got a convergence if you will. There are an unusually high number of unbalanced, strange, and obviously mentally ill people coming into the library on a daily basis. These patrons tend to be male, though there are a few women, and they become regulars, they come every day and stay virtually an entire shift. On average in the past I'd say there were five or six "regulars"; currently I'd put the count at fifteen to twenty.
My co-workers wonder why now? What's occurring to cause this increase. I have to figure it's either economic, or just that public libraries are the last place that people don't have to have a reason to be there. The value and importance of the fact that so much of the world is private sector and that public buildings are far between, is not lost on the likes of me, however, the larger portion of these patrons, are combative and unsettling when we have to engage them if perhaps they've been on the Internet for hours and some one else wants a turn or, they are having trouble with a code they need to break in order to contact the mother ship.