If you don't have the power,find the power within,and find why you need a substance to help you cope with your life,even though you think the substance lets you escape the problem,it doesn't help you it makes the problem worse.
Find the root of the problem and work on the problem.
I did after 4yrs of blaming myself for the Death of my GF in a car crash and hitting rock bottom with depression drink and drugs.
I still smoking ganja and have a beer every so often,though now do all in moderation,and I'm still aware if i have one two many beers I'll drink until i reach oblivion.
Difference is now I have the power to say enough is enough.