Separate model for addiction mechanic? Hmm...
If Lona can use potions without much penalty, then players would use potions more often.
Turning off addiction mechanic would be friendly to new players who are trying to grasp the mechanics of the game.
Switching off addiction mechanic in hard mode should be a good idea, but I afraid changing that might cause more bugs. Since I assume addiction mechanic is deeply intertwined with other mechanics too?