Hikikomori

In Japan it is said that one million young men lock themselves away in their bedrooms.  Some of them block out the daylight.  Mothers leave their food outside their bedroom doors and there is an increase in domestic violence - the parents are sometimes attacked by these frustrated young people.

http://en.wikipedia.org/wiki/Hikikomori

I read a great book about this: http://www.amazon.co.uk/Shutting-Out-Sun-Generation-Departures/dp/1400077796/ref=sr_1_2?ie=UTF8&qid=1335994620&sr=8-2

The hikikomori are male.  There is another term for the females which I cannot remember but was, I think, more derogatory.

It is terrible to have a child who shuts out the sun.  Luckily my child is mostly through that now - but his sensory issues and anxiety did stop him from leaving the house for 1.5 years.