Addiction is two fold, and why it is so hard to overcome. Sometimes addiction is your body screaming for something it is not getting. Examples?
Food addictions, are two fold not enough attention, understanding or love. You turn to comfort food. Addicted to salty snacks? Probably a lack of Magnesium in the diet.
Addicted to sugar? you are looking for a pick me up, for a lack of energy. Probably a B vitamin deficiency, the stress, and energy vitamin.
Addicted to drugs, alcohol, cigarettes? Most all boost dopamine levels in the brain. The everything is fine brain chemical. By supplementing with the right vitamin, or food you wont crave it. To produce dopamine your body requires essential fatty acids, it is either lacking in the diet, or you have a glitch, whereby you aren't able to utilize the fatty acids required for Dopa mine, the b vitamins are also required for re-uptake of all brain chemicals. Serotonin, dopamine, ect. By being addicted to these substances we deplete our bodies of nutrients, don't eat, and thereby just add to the problem, which makes the addiction have a stronger foothold.
My thoughts are not so much will power, but more change the circumstance.