Many people go through the pain and devastation of the illness of depression and do not really have a good grasp on why something like this occurs. It seems so senseless, like such a waste. The reality is something a little closer to a built-in form of ultimate altruism to ensure the survival of people that we care about. A genetic memory to do the “right” thing that we do to help our friends and relatives, even at great cost.
In the course of man’s time on earth, we have survived in small interrelated, supportive, nomadic groups, dealing with hunger and things in the dark with large teeth and claws. Catastrophic loss and injury taps into our individual capacity to come down with the illness of depression, causing us to remove ourselves from the safety of the group, sometimes taking our own life, but just as likely leaving us alone in a hostile world where we become prey. The individual perishes. The group of closely related genes existing in aunts, uncles, sibs, cousins, kin, etc, is no longer caring for us or maybe even literally carrying us. No longer risking all and sharing what may be a meager nutritional supply that already puts the group at risk of crashing. For much of the time man has been on earth, we have lived much of the year right on the edge of starvation. We are a species that survives by helping our friends and neighbors, even to the point of putting the survival of the whole group at risk. Without a built-in mechanism for severing that, there is not a group way to stop the risk, to stop the cost, and to set a limit, even when the whole group becomes at risk of dying.
Depression does that. The individual makes the decision. Removes themself from the community. The community mourns but has a better chance for survival. Much better for our group. Not so good for the individual. Makes sense when living hand to mouth on the Kalahari. Not useful in the excesses of western society, but the biology is still intact. The susceptibility to internal stresses and the substitution of external stress for what used to be very real physical danger still can trigger the inborn mechanism. Sometimes it is set off by no more than the absence of immediate danger to struggle against. Once in a while the mechanism goes awry and kicks off for reasons we do not perceive.
Will be critical for species survival again in 1000 years when the oil and coal and gas run out. Not so much now. In near future, we may even be able to block it so that we at less risk for it kicking off. Hope we don’t forget how to turn it back on generations from now when it is actually needed again.
We are born to be willing to give our lives for the survival of family and friends. The ultimate altruism just happens to be built-in to being human.