Depression is anxiety turned inward.
When people feel anxious and that they don't have control over their situation that make them feel in a sense helpless, and then the anxiety "has no where to go," it becomes depression.
I guess it make sense that if you feel that you can't really do anything to make things better--and no matter how hard you try--then you feel somewhat helpless/hopeless and get depressed
Perhaps it's almost like a frustration at your own inability to change things you feel you need to change.
That is why a person's feeling some sense of control over their environment and life is so important.
When things are looking down, it helps to try and do something to take back control over what feels like spiraling uncontrollable events and circumstances.
Of course, only G-d really has control over what ultimately happens.
But we need to do our part to try to make things better.
Just taking that first (and second and third) step is freeing.
I'm pretty sure that an element of this is that you can tell yourself that you "did everything you could" so in effect there is a lifting of guilt about the situation, but at the same time there is also a genuine feeling that you are here for a purpose and perhaps have made a difference in this world.
Some people feel big and important, but the reality is that we are all so small in a very big world and universe where suffering and loss can strike (G-d forbid) at any moment.
Man is but a speck of dust in the realm of things.
But at the same time, our speck is filled with a soul of the living G-d.
So we must do what we can to be a good influence and impact.
Whatever it is, it is what we can do.
If everyone--7.6 billion of us out there---does their part that can make a difference.
Don't let life's anxieties become your depression.
Look for what you can contribute--do it!--try your best to make a difference and make the world better.
It's what you're here for and what you can positively do. ;-)
(Source Photo: Andy Blumenthal)