Thieving Magpie

I think that that phenomenon is a physical one. For example, building up a resistance to alcohol would (hypothetically) not affect the soul in any way shape or form.

It is true, indulge too much, and it ceases to stimulate but this can usually only be taken so far, and is only true in relation to the body, and not necessarily the spirit, as it is supposed to be non-corporeal.

You will likely find (though I personally have no references currently available to back me up) that as animals, we require, and acquire resistance for physical reasons, which, above all else, cease to apply once we are dead.