This brings to mind a Star Trek TNG episode where two neighboring planets are engaged in a trade dispute. On one planet is a life threatening disease and the other has the cure. The diseased planet produces everything for both planets in payment for the cure. They think they will die without the cure. The other planet lives in luxury and leisure only having to produce a singular cure.

But the cure is not a cure, it is a narcotic. The diseased population isnt sick at all, they have been gaslighted into believing they are. And when they dont get the cure they go through withdrawals, reinforcing this belief.

Not to far from reality, eh?