The metaphor that's always come to my mind is that of living near some sort of singularity, gravitational or otherwise.
Basically, anything that gets too close to the singularity falls inside and disappears. People go around their daily lives, when suddenly someone accidentally gets too close---James Watson?---and Bam! He disappears.
The powerful tidal effects from the invisible singularity warp all sorts of social structures into bizarre shapes and behaviors. Gradually over time, more and more pieces of our world drop inside the singularity and disappear, until eventually the entire society collapses.
Back in the early 1970s, Larry Niven wrote a couple of short stories about the fact that if you just just took a tiny quantum black hole (that was before Hawking's evaporation theory came out) with the mass of a baseball or something and just dropped it into the ground it would fall to the center, swing back and forth through the core, and eventually gobble up the entire planet within a few years or centuries, becoming a somewhat bigger black hole in the process. Tiny black hole plus Earth equals bigger black hole plus no more Earth!
Officially believing in something that just isn't true has much the same impact, eventually gobbling up everything else in your society.