Why shouldn't you smoke weed if you have depression?

Why they have outlawed marijuana use for medical relief is in one word....MONEY. Our government would lose too much money if it were legalized. I do not feel comfortable in this format explaining why and who is benefiting from it being illegal. Is this morally right? Absolutely not. Any form of relief for people with deadly such as cancer or debilitating diseases like MS, also include depression is plain selfish. It is a known fact that alchohol does more damage to our bodies. Personally I do not smoke anything, but my view is it should be legalized.