I just spoke to a coworker from India and he said he had never heard of such a thing until he saw "A Beautiful Mind". Then a discussion developed about the differences between schizophrenic delusions and imaginary friends. Near as I can tell, I think a child knows at some level that their friend doesn't exist. Whereas a delusion is, to the deluded, 100% real.
This East/West theory of mine seems to be holding up.
