Depression is an illness that has plagued man for many years. Increasing in incidence in the development of civilization. That is when civilization or development is defined as more of individualization of the person who used to be very intergrated in the community. People who were always surrounded by all the family members and friends and everybody's business was everybody's business now locked in a prison of privacy where no one knows what is going on with them.
Personally I think privacy has been over-rated. There is peace in sharing what basically goes on in your life, especially the bad things, someone you can trust. Seriously if you think of it, that's the majority of what you do when you see a clinical psychologist. They just allow you to talk and express yourself, "Let it All Out". Something you can do with a friend. But the greatest problem is how to find a good friend to trust with the dark truth of the negative thoughts and ideas that are going through your mind. Someone who won't judgeor condemn you or force you to tell anyone you don't want to or do anything you don't want to.
Why can't we find such people?
1. They all think yout problem is none of their business
2. They're actually not interested in helping you, people are just selfish.
3. They don't have true love, not erotic love, but a true love that empathises and won't stop trying to help.
Basically my take on depression, it's caused by pushing love away, not giving love and therefore not receiving and the increase of evil in the world with so much people do to make them so ashamed to share their lives in detail with others.
All these do not hold in a truly loving Christian community, based on the love of God and the tradition of caring for one another, where one person's property belongs to all or to anyone who needs it at the time and there is no hint of selfish.