There has been a great deal of speculation about the evolutionary significance and origins of depression. What selective advantage does it confer?
Does it allow the patient to concentrate on complex and important problems? Is it a type of pain that, like physical pain, causes us to pull back from danger? Is it a type of behavioral quarantine, causing us to hole up in a safe place while dangers stalk around outside? Perhaps it reduces our libido and our appetite for social interaction in order to stop us getting or giving infectious disease? Is it a simple signal that we need help? Is it a sort of threat to others in our community that, unless they do something to help us, they will have a liability in their midst that could endanger them? Is it a sort of fuse, switching us off and causing us to back down when we are outgunned – so saving us from risky and costly conflicts with our peers?
These suggestions, and the many others in the literature, may seem insulting and insensitive. Isn’t it like asking the point of a disabling road traffic accident?
Well, possibly. But much disease is the result of the malignant transformation or manifestation of a physiological response that is usually useful. Auto-immune illness and allergy, for instance, are damaging consequences of facilities without which we would be dead. So the desire to squeeze depression into the neo-Darwinian paradigm is not necessarily misconceived. What is misconceived, I suggest, is the sheer fancifulness of many of these suggested explanations. Their authors are too clever, ingenious, and imaginative.
Here’s an alternative suggestion, which at least has the advantage of not being so smart.
We need to start by deciding what depression really is. It is, I suggest, an ontological disorder. The main pathology in depression is the erosion or truncation of the Self. Depression robs us of the characteristics that make us us. ‘She’s not herself’, we’ll shrewdly say. The job of a psychiatrist is to ‘put the patient back in their right mind’. Depression makes us sit all day in our bedrooms, facing the wall: cutting ourselves off from all the relationships which define us and make our lives our lives. And if the depression isn’t treated, the threat to the Self can become desperately dangerous. We might annihilate the Self with razor blades or by jumping off a bridge.
Usually, though, the danger isn’t mortal. Most manifestations of depression, for most of us, most of the time, are premonitory signs. They tell us that the Self is vulnerable: that it needs some urgent TLC – or else.
Perhaps it doesn’t need to be stated (it’s really tautological), but of course a sense of Self is vital to our biological survival (which is Darwin’s main interest). It’s my sense of Self that makes me compete for a mate; which makes me look for my next meal; which makes me avoid harming myself.
So: most of the time, depression is acting to preserve the self. It doesn’t just cause us to run away from nasty stressors, as some of the other theories suggest. It acts too as a health education program, teaching us about effective therapies. Once you’ve had a small dose of depression, you recognize the symptoms next time, and reach more quickly for the remedy (whether it’s pills, a holiday, a walk in the sunshine, or a massive dose of friendship).
Depression, then, is a thief of Self which has been cunningly recruited by evolution to frustrate its own burglarious project.
Taken From Blog.OUP.Com