Depression is many things.  There is the kind that comes naturally from negative experiences such as death of a loved one, a sickness or failure. I call this "normal depression".  Then there is the kind that comes from chemical imbalances that may be more tied in with the body and its complex glandular system.  This is "physiological depression" and can be caused by a number of factors including drugs, bad diet, and abnormalities of the internal organs, hormonal fluctuations or hereditary reasons.

The trickiest kind, in my opinion, is that kind of depression which is the result of faulty thinking or errant belief.  It is the kind of thinking that makes a teenage boy think he has no future because his temporary troubles seem so large and overwhelming. Teen suicide. It is the kind of thinking that makes a preacher think he is useless and a failure, when in reality (God's view of things) he is doing a great job.

This depression is what I call "cognitive depression" in that it is based inside ones own head with little or no basis in reality.  Often the reason for this is a lack of a reference point or a faulty reference point.  Not knowing where you are creates the fear or the assumption that you are nowhere.  Thinking you are not where you should be assumes that you are an accurate assessor of where you
should be.  We are not.

Therefore, this kind of depression is a spiritual problem and it can lead to mental and physical problems.  Hope, faith, love and trust in God along with a renewed emphasis on working will combat physical depression.  There are two human factors behind it:  1. Pride (The example of Elijah "I am not BETTER than my fathers" Who said you had to be better than anyone?)  and 2. Fear.  Perfect love casts out fear.  I am convinced that if we can deal with these two things we can go a long way to getting over depression in our own lives and help others
to gain victory as well.

One thing I have found is that most depressed people have way too much time on their hands.  Some, in the absence of any real challenges or difficulty, will imagine or create the same except these manufactured problems cannot be solved or won over in reality because they do not really exist except in their minds.

For example, Hypochondriacs will often lose their strange, illusive symptoms when they acquire an actual illness.  I once pastored a woman who always had some stomach problems or headaches. She had gone to many doctors and was on all kinds of medicine.  She once fell down some steps and broke her leg.  For several weeks she was healthier and felt better than she had in years!  She had a real problem that she could focus her energy on and it relieved her of the imaginary ones. 

I think this may be why we have so much "angst" among our youth.  Our affluence has shielded them from real difficulty so they lack a reference point. The youth of the Great Depression or World War Two had too much real trouble to spend their thoughts on how bad things are. Maybe this is the reason behind piercings and other self inflicted pain.  Those who are getting real cuts, blisters and bruises from working a physically demanding job are generally not as interested in poking holes in themselves.  They may do it to conform to a fad but they probably wouldn't think of it themselves.

With the exception of those whose depression is the result of burnout (another issue but very related) I have prescribed them to get a job or add to their daily activities.  Doing something good for others is the best cure I know for those whose depression is the result of being too inactive and self absorbed.

I could say a lot more but these are just some of my observations   gained through my years of ministry.