Revelation or Fear: The Two Scenarios of a Split-Reality

An experience and/or sensation that people are having in greater frequency recently is that of being in a ‘different reality’ from other people. I have heard it spoken that someone can be standing right next to another person and yet it feels like both are living in a completely different reality. Is this a new human condition – the ‘split-reality syndrome’? And if so, what are the principal aspects of these different realities?