Many of the people I have interviewed take antidepressants for “mild depression,” and they lead happier and better lives because of it. I’d do the same. Perhaps what they want to change is really personality, as Peter Kramer suggested in Listening to Prozac. The news that depression is a chemical or biological problem is a public relations stunt; we could, at least in theory, find the brain chemistry for violence and monkey around with that if we were so inclined. The notion that all depression is invasive illness rests either on a vast expansion of the word illness to include all kinds of qualities (from sleepiness to obnoxiousness to stupidity) or on a convenient modern fiction. Severe depression, nonetheless, is a devastating condition that is now treatable, and it must be treated as vigorously as possible, for the sake of a just society in which people live rich, healthy lives. It should be covered by insurers, protected by acts of Congress, addressed by great researchers as a matter of the utmost importance. There is an apparent paradox here that points to existential questions about what constitutes the person and what constitute his afflictions. Our rights to life and liberty are comparatively straightforward; our right to the pursuit of happiness becomes more puzzling every day.
An older friend of mine once said to me that sex had been destroyed by its public existence. When she was young, she said, she and her first lovers discovered a new thing with only their roughest instincts to guide them. They had no specific expectations of one another, no standards. “You have read so many articles about who should have how many orgasms when and how,” she said to me. “You have been told what to do and in which positions and how to feel. You have been told the right way and the wrong way of everything. What chance of discovery do you have now?”
Dysfunction of the brain too was once a private affair, the history recounted in this volume notwithstanding. One came to it with no expectations, and how things went wrong was largely individual. How those around you dealt with it was also individual. Now we enter into psychic pain within guidelines. We thrive on artificial categorizations and reductive formulae. When depression tumbled out of the collective closet, it became an externally ordered sequence. That is where politics meets depression. This book itself is helplessly enmeshed in the politics of the disease. If you read these pages closely, you can learn how to be depressed: what to feel, what to think, what to do. Nonetheless, the individuality of every person’s struggle is unbreachable. Depression, like sex, retains an unquenchable aura of mystery. It is new every time.
CHAPTER XI
Evolution
A great deal has been said about the who and what and when and where of depression. Evolutionists have turned their attention to the why. The interest in the why begins with the historical: evolutionary biology explains how things came to be the way they are. Why would such an obviously unpleasant and essentially unproductive condition occur in so large a part of the population? What advantages could it ever have served? Could it be simply a defect in humanity? Why was it not selected out a long time ago? Why do particular symptoms tend to cluster? What is the relation between the social and the biological evolution of the disorder? It is impossible to answer without looking at the questions that precede the matter of depression. Why, in evolutionary terms, do we have moods at all? Why indeed do we have emotions? What exactly caused nature to select for despair and frustration and irritability, and to select for, relatively speaking, so little joy? To look at the evolutionary questions about depression is to look at what it means to be human.
It is evident that mood disorders are not simple, singular, discrete conditions. Michael McGuire and Alfonso Troisi, in their book Darwinian Psychiatry, point out that depression “can occur with and without known precipitants, can sometimes run in families and sometimes not, can show different concordance rates among monozygotic twins, can sometimes last a lifetime and at other times remit spontaneously.” Further, depression is obviously the common outcome of many causes; “some persons with depression grow up and live in adverse social environments while others do not; some come from families in which depression is common while others do not; and significant individual differences in depression-causing physiological systems (e.g., norepinephrine, serotonin) have been reported. What is more, some respond to one type of antidepressant medication but not to another; some do not respond to any type of medication but do respond to electroconvulsive treatment; and some do not respond to any known intervention.”
The suggestion is that what we call depression seems to be a peculiar assortment of conditions for which there are no evident boundaries. It is as though we had a condition called “cough” that included some cough that responds to antibiotics (tuberculosis) and some cough that responds to changes in humidity (emphysema) and some that responds to psychological treatments (cough may be a neurotic behavior) and some that requires chemotherapy (lung cancer) and some that appears to be intractable. Some cough is fatal if untreated and some is chronic and some is temporary and some is seasonal. Some goes away on its own. Some is related to viral infection. What is cough? We have decided to define cough as a symptom of various illnesses rather than as an illness of its own, though we can also look at what might be called the consequent symptoms of cough itself: sore throat, poor sleep, difficulty with speech, irritating tickly feelings, troubled breathing, and so on. Depression is not a rational disease category; like cough, it is a symptom with symptoms. If we didn’t know about the range of illnesses that cause coughs, we would have no basis for understanding the “refractory cough” and we would come up with all kinds of explanations for why some cough seems to resist treatment. We do not at this time have a clear system for sorting out the different types of depression and their different implications. It is unlikely that such an illness has a single explanation. If it occurs for a whole catalog of reasons, one must use multiple systems for examining it. There is something inherently sloppy about the current modes, which take a pinch of psychoanalytic thinking and a little bit of biology and a few external circumstances and throw them together into a crazy salad. We need to disentangle depression and grief and personality and illness before we can make real sense of depressed mental states.
The most basic animal response is sensation. The experience of hunger is unpleasant and the feeling of satiety is pleasant for all living creatures, which is why we make the effort to feed ourselves. If hunger were not a disagreeable sensation, we would starve. We have instincts that lead us to food, and when those instincts are foiled—by the unavailability of food, for example—we experience extreme hunger, a condition we will do almost anything to alleviate. Sensations tend to trigger emotions: when I am unhappy about being hungry, I am having an emotional response to a sensation. It appears that insects and many invertebrates have sensation and response to sensation, and it is difficult to say where in the animal hierarchy emotion begins. Emotion is not a characteristic exclusively of the highest mammals; but it is also not an appropriate word to use in describing the behavior of an amoeba. We are afflicted with the pathetic fallacy and have an anthropomorphic tendency to say, for example, that an underwatered plant is unhappy when it droops—or, indeed, that the car is being grumpy when it keeps stalling. It is not easy to distinguish between such projections and true emotion. Is a swarm of bees angry? Is a salmon going upstream resolute? The highly regarded biologist Charles Sherrington wrote in the late forties, when he looked through a microscope at a flea biting, that “the act whether reflex or not, seemed charged with the most violent emotion. Its Lilliput scale aside, the scene compared with that of the prowling lion in Salambo. It was a glimpse suggesting a vast ocean of ‘affect’ pervading the insect world.” What Sherrington describes is how action appears to the human eye to reflect emotion.
If emotion is a more sophisticated matter than sensation, mood is a yet more sophisticated idea. The evolutionary biologist C. U. M. Smith describes emotion as weather (whether it’s raining out right now) and mood as climate (whether it’s a damp, rainy part of the world). Mood is a susta
ined emotional state that colors responses to sensation. It is made up of emotion that has acquired a life of its own quite outside of its immediate precipitants. One can be unhappy because of hunger and get into an irritable mood that will not necessarily be alleviated by eating something. Mood exists across species; in general, the more developed the species, the more powerfully mood occurs independent of immediate external circumstance. This is most true in people. Even those who do not suffer from depression have blue moods sometimes, when little things seem to be full of reminders of mortality, when those who are gone or those times that are gone are missed suddenly and profoundly, when the simple fact that we exist in a transient world seems paralyzingly sad. Sometimes people are sad for no apparent reason at all. And even those who are frequently depressed sometimes experience high moods when the sun seems extra bright and everything tastes delicious and the world is explosively full of possibilities, when the past seems like just a little overture to the splendor of the present and the future. Why this should be so is both a biochemical and an evolutionary puzzle. The selective advantages of emotion are much easier to see than the species’ need for mood.
Is depression a derangement, like cancer, or can it be defensive, like nausea? Evolutionists argue that it occurs much too often to be a simple dysfunction. It seems likely that the capacity for depression entails mechanisms that at some stage served a reproductive advantage. Four possibilities can be adduced from this. Each is at least partially true. The first is that depression served a purpose in evolution’s prehuman times that it no longer serves. The second is that the stresses of modern life are incompatible with the brains we have evolved, and that depression is the consequence of our doing what we did not evolve to do. The third is that depression serves a useful function unto itself in human societies, that it’s sometimes a good thing for people to be depressed. The last is that the genes and consequent biological structures that are implicated in depression are also implicated in other, more useful behaviors or feelings—that depression is a secondary result of a useful variant in brain physiology.
The idea that depression at one time served a useful function that it no longer serves—that it is in effect a relic—is borne out by our many vestigial emotional responses. As the psychologist Jack Kahn has pointed out, “People do not have a natural fear of real dangers like cars and light sockets, but waste their time and energy being afraid of harmless spiders and snakes”—animals it would have been useful to fear in a different time at a different stage of our development as a species. Following this pattern, depression often clusters around what seem to be utterly unimportant matters. Anthony Stevens and John Price have proposed that some form of depression is necessary for the formation of primitive rank societies. Though lower organisms and some higher mammals, such as the orangutan, are loners, most advanced animals form social groupings, which furnish better defense against predators, better access to resources, greater and more accessible reproductive opportunities, and the prospect of cooperative hunting. There is no doubt that natural selection has favored collectivity. The impulse toward collectivity is extremely strong in human beings. We inhabit societies and most of us rely heavily on the sense of belonging. Being well liked is one of life’s great pleasures; being excluded, ignored, or in some other way unpopular is one of the worst experiences we can have.
Someone is always top dog; a society without a leader is chaotic and soon dissolves. Usually the positions of individuals within a group are subject to change over time, and the leader has to keep defending his position against challengers until he is ultimately defeated. Depression is critical to the resolution of conflict about dominance in such societies. If a lower-ranking animal challenges the leader and doesn’t get discouraged, he will keep challenging the leader and there will be no peace and the group will not be able to function as a group. If, upon losing, such an animal stops being self-assertive and withdraws into a somewhat depressed state (one characterized more by passivity than by existential crisis), he thereby acknowledges the winner’s triumph, and he accepts perforce the dominance structure. This subdominant figure, by yielding to authority, frees the winner from the obligation to kill him or to expel him from the group. So through the appropriate occurrence of mild to moderate depression, social consonance can be achieved in a rank-based society. That those who have suffered depression frequently relapse may indicate that those who have fought and lost ought to avoid fighting again, so minimizing damage to themselves. The evolutionist J. Birtchnell has said that brain centers are constantly monitoring one’s status in relation to others, and that we all function according to internalized notions of rank. The result of a fight will determine how most animals rank themselves; depression can be useful in preventing such animals from challenging their rank when they have no real chance of improvement. Often, even if not engaged in improving social position, people suffer the criticism and attack of others. Depression pulls them out of the territory in which they are subject to such criticism; they disengage so that they do not get put down (this theory seems to me to have a bit of a sledgehammer-to-mosquito problem). The anxiety element of depression is then tied to the fear of being the object of such vigorous attack as to be excluded from the group, a development that in animal societies and in human hunter-gatherer times would have had fatal consequences.
This particular argument for the evolutionary structures of depression is not highly relevant to depression as we now experience it in societies that have enormous numbers of external structuring principles. In pack-animal societies, group structure is determined by physical strength expressed through fights in which one party triumphs over the other by diminishing or defeating it. Russell Gardner, for many years the head of the Across-Species Comparisons and Psychopathology (ASCAP) Society, has looked at how human depression is linked to animal models. He proposes that, in humans, success is less contingent on putting down others than on doing things oneself. People are not successful solely on the basis of their preventing anyone else from being a success; they succeed because of their own achievements. This is not to say that one is entirely free of the business of competition and of doing injury to others, but the competition that characterizes most human social systems is more constructive than destructive. In animal societies, the essential subject of success is “I’m stronger than you,” while in human societies it is to a greater degree “I’m fantastically good.”
Gardner proposes that while actual testable strength determines the animal social order, with those who are weak developing depressionlike states, in human societies, public opinion determines the social order. So while a baboon might act depressed because each of the other baboons can (and does) beat him up, a human being might become depressed because nobody thinks well of him. Still, the basic rank hypothesis is borne out by contemporary experience—people who lose rank do become depressed, and that can sometimes make them more accepting of a lower rank in society. It should be noted, nonetheless, that even those who refuse to accept lower rank are not usually thrown out of contemporary societies—some of them, indeed, become respectable revolutionaries.
Depression is an agitated cousin of hibernation, a silence and withdrawal that conserves energy, a slowing down of all systems—which seems to support the idea that depression is a relic. That depressed people long for their own bed and don’t want to leave the house evokes hibernation: an animal should hibernate not in the middle of a field but in the relative safety of its cozy den. According to one hypothesis, depression is a natural form of withdrawal that must take place in a secure context. “It may be that depression is associated with sleep,” Thomas Wehr, the sleep man at the NIMH, has suggested, “because it’s really associated with a place where sleep occurs, with being at home.” Depression may also be accompanied by altered levels of prolactin, the hormone that causes birds to sit for weeks on end on their eggs. That’s also a form of withdrawal and quiescence. Of milder depression, Wehr says, “The members of the species who were too anxious
to deal with crowds, didn’t go to high places, didn’t enter tunnels, didn’t single themselves out, shied away from strangers, went home when they sensed danger—they probably lived long and had lots of babies.”
It is important to bear in mind evolution’s putative singularity of purpose. Natural selection does not wipe out disorders or move toward perfection. Natural selection favors the expression of certain genes over other genes. Our brains evolve less rapidly than our way of life. McGuire and Troisi call this the “genome-lag hypothesis.” There is no question that modern life carries burdens incompatible with the brains we have evolved. Depression may, then, well be a consequence of our doing what we did not evolve to do. “I think, in a species that’s designed to live in groups of fifty to seventy,” says Randolph Nesse, a leader in evolutionary psychology, “living in a group of several billion is just hard on everyone. But who knows? Maybe it’s diet, maybe exercise rates, maybe changes in family structure, maybe changes in mating patterns and sexual access, maybe sleep, maybe having to confront death itself as a conscious idea, maybe none of these.” James Ballenger of the Medical University of South Carolina adds, “The stimuli for anxiety just weren’t there in the past. You stayed within easy distance of home, and most people can learn to deal with one place. Modern society is anxiety-provoking.” Evolution invented a paradigm in which a particular response was useful in particular circumstances; modern life provokes that response, that constellation of symptoms, under many circumstances in which they are not useful. Rates of depression tend to be low in hunter-gatherer or purely agricultural societies; higher in industrial societies; and highest in societies in transition. This supports McGuire and Troisi’s hypothesis. There are a thousand difficulties in modern societies that more traditional societies did not have to face. Adjusting to them without having time to learn coping strategies is nearly impossible. Of these difficulties, the worst is probably chronic stress. In the wild, animals tend to have a momentary awful situation and then to resolve it by surviving or dying. Except for persistent hunger, there is no chronic stress. Wild animals do not take on jobs that they regret; do not force themselves to interact calmly, year after year, with those they dislike; do not have child custody battles.
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