Survival. Protection. Energy conservation.

I've thought before about why depression is so common. Being a biologist and knowing that at least some depression has a biological basis, it means that evolution has selected for this trait for thousands and thousands of years. What could be so valuable about depression that it would be preserved over the millenia? I was taking this interdisciplinary course on Addiction a year or two ago and we looked at some interesting research that related to this question of mine about depression. I learned about "learned helplessness" in animals and how it is thought this may be similar to depression in humans (similar biochemistry in the two situations). Here are a couple of examples of learned helplessness. When 2 mice (or rats) are in a cage together and one is dominant and will beat the c**p out of the other, the less dominant one does this "learned helplessness" behavior where it will just lie there and not move or fight or anything. The dominant rodent will leave it alone when it does this. So the less dominant mouse lives to see another day. Very valuable behavior! Another example is the swim tank experiment with mice. If you put a mouse in a swim tank it will swim around until by trial and error it finds a small platform hidden just under the water's surface where it can rest. If there is no swim platform, the mouse would eventually drown (sounds cruel, but they don't let them drown). In normal mice, when the mouse has exhausted the possibilities and looked all over the tank and not found a platform, it gives up and goes into the so-called "learned helplessness" behavior and just goes limp and floats on the surface of the water expending as little energy as possible. In this way, it can remain alive as long as possible, and if environmental conditions should change (the water is let out of the tank, a researcher rescues it, a platform suddenly appears), it is alive to take advantage of the change of events. If it had continued to swim around frantically, it would have died. Interestingly, when the gene for a brain chemical that induces depression in mammals (humans too) is eliminated by gene tinkering, the mice seem normal in most respects but are unable to do the "learned helplessness" behaviors. So they will swim around the tank frantically, wasting all their energy, and drown sooner than their chums who are still able to be depressed. So this sort of behavior has huge adaptive/survival value in certain circumstances.

There are more experiments too. Learning all this allowed me to give some meaning to my depression. It was easy to get down on myself for being depressed (the you-should-be-able-to-pull-yourself-up-by-your-bootstraps mentality), but now I saw that depression did have adaptive value (explaining why it had been preserved by evolution). I saw then that my being depressed had protected me in a bad situation in my life, allowed me to survive in what seemed a hopeless situation, and conserve energy until a better day came along. It wasn't much fun when I was in the middle of it, but I see now it was a very natural way to react to circumstances and my body/brain was just trying to protect me and help me live to see another day. I talked about this with my therapist a couple of times and he said also that being so depressed allowed me to stay in my marriage longer, and this did have some value, no matter how unhappy I may have been. My children got to be in a two-parent home for most of their childhood, and I think this had a lot of advantages for them. Material resources for one, but also more parental attention since there are 2 parents instead of only 1 (at a time). The depression helped numb me to the situation and allowed me to tolerate it.

Anyway, this interpretation really helped me make peace with my depression as I saw it had had some value. I felt like I could shake hands with it and be at peace. I know this interpretation probably isn't going to fit all people, but it made a lot of sense in relation to my situation. Now better times have come, and I don't need to be depressed anymore. There is no value now. And I'm not depressed. (I have found the hidden platform under the water.)