Not everyone fits into society. Dropping out, or falling by the wayside, has numerous causes and many manifestations.

Two categories cover the more extreme forms — homelessness and hikikomori, a withdrawal from all social activities into the security of one's own room, usually in one's parents' home. The former is characteristic of the West, the latter more typically Asian.

In Japan, roughly 700,000 individuals are in a state of hikikomori, according to government figures released in July 2010. Their average age is 31. The oldest among them, known as the "first-generation hikikomori," are now in their 40s, having isolated themselves from almost all human contact for more than 20 years. Then there are the borderline cases, the 1.55 million people the government finds are more or less on the verge of shutting themselves up in their rooms.