Depression is when the distance between ‘What is’ and ‘What I want/What should be/’ gets great enough to break the chain of hope.
The ‘What is’ and ‘What I want’ are always playing a game of cat and mouse with each other.
‘What is’ —————— —-(The pull of passion, hope, belief, meaning)—>>>>>> ———-‘What I want’
When the rift between them gets too large, the tension of passion, hope and belief loses its power and gets disconnected.
‘What is’———– ……………(long distance)…….. ———-‘What I want’
Another case is when, you want all kinds of contradictory realities which are not possible, like equally want to experience being married and single, being celibate and sexual, living in a cave and enjoying worldly games and so on. I mean why would you want to forgo anything?
So then too, the bridges between ‘What is’ and ‘What I want’ are broken
‘What is’ ———————————————–‘What I want 1’
————————————‘What I want 2’
————————————‘What I want 3’
————————————‘What I want n’
Which one will you take if there are 1000s of them? And for each one you’ll need an entirely different structure. And each one of these realities would take enormous time to create and nurture? How can you have all of them? Each is a parallel universe of possibilities.
So, as you contemplate ‘what I want’, the desires reach more and more lofty unattainable contradictory impossible levels. Correspondingly the distance/bridges between ‘What is’ and the ‘What I want’ gets so large, that the hope/passion/belief/meaning gets broken. When you see the futility and the impossibility of the task of getting to ‘What I want’, you resign and get depressed.
Now everything that happens in ‘What is’ is unsatisfactory to ‘What I want’ and since the bridge itself is broken, you are just doing things but with the baggage of great dissatisfaction.
Now the only way out is to dissolve the ‘What I want’ and stay with the ‘What is’. Staying with the ‘What is’ continuously 24×7 as a practice, in time, will create enough counter karma to remove the karma of maintaining ‘What I want’. Another way to satisfy your intellectual side would be to see the logical impossibility of getting ‘What I want’. This is because, you cannot get the infinite by any conception of ‘What I want’. And the Infinite >>>>>>>>>>>>>>>>>>>>>>> What I want. So to that degree your dissatisfaction would also be EXTREMELY high because you want the infinite, but you only get a single conception with your egoic efforts.
Journey to the Abstract 
I’ll touch upon one concept at a time in my comments.
There are lots of dichotomies that exist in life and thousands more that you can find if you search, because there are thousands of ways of looking at things. I think you can choose to include one or another dichotomy in your reality, and choose other dichotomies to not be a part of your reality. What is in your reality includes what you give focus to. People around you may possess the dichotomy that you either confront someone about something that is bothering you, or you will end up harboring resentment against them. And somewhere down the line you’ll end up blowing your top over these things you held onto inside and never expressed. Well there may be “a whole ‘nother” route that exists that these people are blind to, because in their reality it is either this or that. So, rather than seeing the trails that branch off of that particular scenario that only leads to a set destination, their view and experiences are limited to those…..limitations.
The way one chooses is by analyzing each dichotomy that presents itself to your brain. Some that other people hold may not even be a truth to you, (the one in particular I detailed is one I find not to be true…but many people around me speak that way). Does it fit with other truths you hold? But also, sometimes a dichotomy is true in a particular situation, and in another is not. Is it even worthwhile to think about or important? People have the ability to pull problems out of thin air
Even if something seems insurmountable…. examples would be a typical guy in America with his “biological need” to copulate or he won’t be able to focus properly in the rest of his life, or not being able to be fully happy without finding someone to be in a relationship with, or the reality that being the center of attention will always, no matter what, be an unpleasant experience for that person with an anxiety-prone makeup…..I believe that the simple act of acknowledging it, thinking along those lines, living that truth, gives it part of its power and solidifies the reality of it. These so-called facts are ideas you are putting above yourself and above your experiences. They become regulating factors, necessarily limiting your viewpoint. Even if, perhaps, the odds of it being absolutely solid in and of itself has a 99% advantage, it is still up to you whether to give it a designated honorary spot in your brain and the degree you let it influence your thought processes.
Seeing, or more accurately focusing on the fact that “this” leads to “that” or having “this” will deprive me of “that” is literally placing yourself in a position of subservience that may not serve to influence the course of your life in any positive or productive way. And just as importantly does not leave room for a reality other than that dichotomy, which you may discover somewhere along the way if you keep your mind open.
“Depression is when the distance between ‘What is’ and ‘What I want/What should be/’ gets great enough to break the chain of hope.”
I think this is a pretty good way of conceptualizing the phenomenon of depression. I do think that as long as something seems within reach, a person won’t get too down, unless they want to focus on the negative. But I guess focusing on the negative is an act of acknowledging that things are getting out of hand, out of reach for them. From my experience, I was able to maintain a satisfactory state of existence for a long time – 9 years. Though I was in a state of depression because there was a void/disruption/incongruence in my existence, having hope and being in touch with a reality that did not contain that depression kept me in a relative state of homeostasis….one that was kind of below the line of ideal, but didn’t sink me below the surface where I would drown, where the void was strong enough to overpower my essence.
“When the rift between them gets too large, the tension of passion, hope and belief loses its power and gets disconnected.”
The tension you talk about is a cool concept to bring up, like the basic elements that make up the life force, and buoys the will to live; a certain interplay and balance of those drives. Then, like in your visual picture of the rift stretching longer and longer between your perceived actual reality and what you wish to be your reality, it’s like tearing the electrons further and further from the nucleus and the bond will be less strong, less centralized. Your ‘self’ is dispersing. A darker ‘void’ force is reigning rather than what one would experience as the positive vibration of the more self-initiating life-bringing active interaction of passion, hope/dreams, belief and receptivity. A healthy state of mind is how I see it.
In depression, that bond that is keeping you connected to life has weakened considerably, whether it be by means of slow erosion or a sudden instance that shatters your ‘good reality’. In a depressive state, everything seems to not be of importance. Things in general seem liess solid. One’s vision in a sense is skewed. In the case of major depression, where you won’t be springing back to the ‘normal you’ anytime soon, your whole life is in disarray – it’s gotten to your core and is disrupting the healthy interplay of the vital basic elements which sustain a fulfilling presence in and engagement with life. And, as you said, everything in your reality comes to be under the category of unsatisfactory, because you are constantly in this state of unfulfillment and feeling fragmentated.