I think that in a way depression is just like Cancer. It shows you all those signs that you have it. The helpless feeling, how alone you feel when you are surrounded with people, how you feel like everyone is plotting against you or waiting for you to make a mistake so they could criticise you. And when you do acknowledge the fact that maybe you do have depression you are in denial. No, it can't be. Why me? I am just down today tomorrow for sure I will be better. And tomorrow comes and you are not better the days roll away one by one and you get deeper and deeper into the killing disease. And when you try, try to seek help, you could be too late. They tell you , you are in too deep now we don't know if we can save you, we will try our best. And their best is sometimes not enough. Some people never get over that disease and die with it while others are okay now because really. depression isn't cured once and for all it simply goes into a state of comma waiting for when you are weak to strike again.
But while cancer tortures you for a certain amount of time then you die, depression is there for as long as you will let it. Slowly killing you till you become nothing but a walking corpse and a shell of who you once were.