Fascinating, lenghty article in today's NY Times on a phenomenon in Japan: hikikomori.
There are, apparently hundreds of thousands of young Japanese, mostly men, who shut themselves up in their rooms and never really join society. It typically starts in their teens and can last for years, even decades. And for some it never stops. The problem ends up being far more serious than just how it affects those individual lives. There are hundreds of thousands of Japanese parents who find themselves taking care of their grown children, even delaying their own retirement.
And not only can't those who are actively shutting themselves away contribute fully to society, but they are often, even if they do emerge, unable to ever really re-enter society fully, staying on the margins of employment, education and social circles.
I'm not sure why the article doesn't cite any experts who think this is a kind of agoraphobia. It seems like these hikikomori (yes, it can be used as a noun to describe the syndrome and the person who has it) aren't so much afraid of the outside world, but more afflicted with a deep lethargy and apathy and hopelessness. They're not afraid to go out in the world...they just can't think of a compelling reason to do so.
The differences between Japanese and American society seem pretty stark. The pressures that create hikikomori, the lack of alternative outlets for Japanese teens who feel "different", the apparent reluctance to trundle kids off to therapy and then medication.