Imagine that our moods were represented as us being a submarine in the ocean. The greater the depth, the greater the depression. With the surface being, ‘Okay, no current depression’.
This submarine has submarine controls that allow you to bring in or expel water to change your depth. It also has ‘wings’ or diving planes. The faster you go forward and the greater a degree you adjust them to the faster your depth changes.
At 50 feet under the water you can expend the energy and expel the water for your submarine, and mood, to rise & improve.
At 300 or 400 feet it takes a little more effort. At 1,000 feet you have to move forward and adjust the diving planes.
As you go deeper, and the pressure increases from all directions, it takes exponentially more effort than before to traverse the same vertical distance. And pressure on the submarine increases the control surfaces become harder to control.
At 2,000 feet the pressure makes it harder to adjust the dive planes.
At 10,000 feet there is too much pressure to expel water and it’s very hard to expend the energy to move forward fast enough (remember you’re under hundreds of atmospheres) and adjusting the dive planes takes much more force to hold them at the correct angle.
And ultimately the depth is so deep that you cannot effectively control the vehicle and the pressure will keep it submerged, push it further down or crush it.
At 50 feet you can develop habits that help.
At 500 feet it’s harder to do it on your own (without some outside super-ship winching you up).
And at 5,000 feet it may be impossible to control at all without significant force exerted from an outside source.
Depression is pressure that degrades the effectiveness of your control surfaces – and there is a cross over point at which you cannot effectively direct your own behaviour anymore. You know what you want the submarine to do but you no longer have control of it. So when you’re doing well and getting better you work on habits. God forbid you ever experience the levels of despondency and despair and hopelessness that severe depression brings you need to be gentle with yourself and look for help.
(I am not a professional, just someone who is interested and has some experience and enjoys broadcasting his experiences into the void.
Also all the numbers for submarines depths are completely arbitrary and used to illustrate the idea of greater depth making it require more energy and making it harder to act).