Not sure I get the question. I think this might help. Your body becomes in need of the opoid much like it needs water. If you lack water you die. If you lack opoids your body reacts in such a way that its almost impossible to not go back to the drug. Following pro-longed use of the opoid your body simply can't stand the fact that you are not giving it what it needs. It gets pissed and lets you know in a way that is hard to overcome.