Authors: Barbara Natterson-Horowitz
Needless to say, tattooing is not the same as self-injury. It’s an ancient and, in many places, sacred cultural art form. But it
is
a kind of grooming that bears many similarities to the practices of our primate cousins. It’s an intimate interaction between two individuals. It often confers social status. The pain involved in getting a tattoo releases endorphins.
The zoobiquitous notion that self-injury is a form of grooming gone wild opens up a whole new way of looking at our society’s increasingly painful and invasive preening rituals. We subject ourselves to full-body waxing, genital bleaching, acid peels, repeated electrolysis, cuticle shaving, adult orthodontia, ultraviolet tooth whitening, laser microplaning, and Hollywood’s injection of choice, Botox.
Whether their tool is a tattooist’s ink gun, a plastic surgeon’s needle, a cutter’s razor blade, or their own talons and beaks, sometimes humans and animals simply cross a line. And when this line is crossed, healthy self-care may shift toward significant self-harm. We may not be able to define exactly where that line begins, but we can easily spot when someone has crossed it.
All of us—from full-blown cutters to secret hair pluckers and nail biters—share our grooming compulsions with animals. Grooming represents a hardwired drive, one that’s evolved over millions of years with the positive benefits of keeping us clean and binding us socially.
Parents, peers, physicians, and vets should take notice when stress, isolation, and boredom appear. Combating these triggers with the fellowship of a theater group, the primal satisfaction of backyard gardening, or the grooming challenge of a carefully placed wad of gum does more than create a distraction. It uses an evolutionary tool set to repair an evolutionary short circuit.
*
Twenty-five years ago, when I was a medical student on the inpatient psychiatric unit at U.C. San Francisco, self-mutilation was thought to be uncommon in general populations. It was typically diagnosed in conjunction with a developmental or psychotic disability—for example, eye gouging or genital cutting with schizophrenia or head banging with autism. Indeed, self-mutilation occurs in association with certain disorders, including Tourette’s syndrome, Lesch-Nyhan syndrome, some forms of developmental delay, and borderline personality pathology.
†
Lack of suicidal intent is a relatively new notion when it comes to self-injury—in fact, some of what just twenty years ago we called “hesitation marks” (scars or shallow wounds) on the wrists of a suicide might actually have been evidence of previous cutting.
‡
In the fourth version of the
Diagnostic and Statistical Manual of Mental Disorders
(DSM-IV), self-harm is listed as a symptom of borderline personality disorder. Other psychiatric texts classify it as an impulse-control disorder, along with exhibitionism, kleptomania, and the compulsive tics and vocalizations of Tourette’s syndrome. The much-anticipated
DSM-V
will likely recategorize acts of nonsuicidal self-harm, including cutting, based on our expanded understanding of the neurobiology and genetics that underlie them.
§
Besides hair twirling and nail biting, many of us chew gum when we’re stressed out. Zoobiquitously, some nonhuman primates in the wild pick gum arabic (the springy, saplike base of natural chewing gums) out of trees and chew it. Zoo behaviorists sometimes give their primates this substance as a way of combating stereotypies. Some nonnutritive chewing has, indeed, been shown to have a calming effect, at least depending on which teeth you use (one group of dentists claims that chewing with the rear molars is more relaxing, while using the front teeth or canines perks you up).
‖
Before addressing these common causes, vets rule out underlying medical conditions. Psychiatrists do this, too, when a new symptom presents. For example, when a patient has a new presentation of depression, the physician may consider hypothyroidism, Cushing’s syndrome, or even pancreatic cancer. Similarly, when an animal (human or otherwise) presents with self-injury, organic causes, including physical pain, must be excluded first.
a
Most reports of animal self-harm come from captive populations, and in some circumstances, captivity itself may exacerbate the triggers. But captive settings aren’t the only places animals experience stress, isolation, and boredom. Comparable behaviors may well occur in the wild, too—but given the difficulties and limitations of observing free-ranging animals, wild versions are probably underreported.
b
In 1985, the USDA laid out six elements it deems critical to the psychological well-being of captive animals: social grouping; structure and substrate (meaning the environment of the cage and its flooring, bedding, perches, etc.); foraging opportunities; toys or manipulables; stimulation of all five senses; and training.
The eating disorders unit of a psychiatric hospital takes on a charged atmosphere around 6 p.m. every day, when leaf-thin patients float anxiously into the dining room. Many are draped in a concealing uniform of baggy sweatpants and oversized shirts with sleeves so long only their fingertips peek out. They glance around warily, eyeing one another and slyly sniffing the air to predict what food they will be challenged to swallow. The meals have been calibrated down to the last calorie and garnished to entice the most reluctant eater. Kind but guarded, the nurses, doctors, and ward assistants (including the janitors) are on high alert for food avoiders, food hiders, and food purgers. Sometimes they lock the bathroom doors before serving time to make sure no one slips away for a mid-meal regurgitation.
As a psychiatry resident in the late 1980s, I spent six months rotating through the eating disorders unit at the UCLA Neuropsychiatric Institute. I remember a meal with one particular patient, a fourteen-year-old I’ll call Amber. Pale and gaunt, she sat next to me at the round faux-wood table, fixated on the green plastic plate in front of her. On it sat a simple turkey sandwich and a red apple. She stared at the meal. And she stared.
Finally she looked up at me. I was surprised to see something like terror in her eyes. “I can’t do it,” she whispered. “I just can’t. I am scared to eat this food.”
Scared to eat. I remember thinking to myself how disordered that seemed. How unnatural. Even before I had become used to taking a comparative approach to human medical conditions, I thought, here is a mental disorder that is completely antithetical to the principles of evolution. In the wild, animals that starved themselves on purpose would be on a collision course with extinction.
And yet this form of self-starvation, called anorexia nervosa,
strikes 1 in 200 American women.
It’s surprisingly lethal. Killing up to 10 percent of the afflicted, anorexia is considered to be the deadliest psychiatric disorder among young females.
Bulimia nervosa, the well known binge-purge disorder, affects some 1 to 1.5 percent of women at some point in their lives and .5 percent of men. And there’s also a rapidly expanding category of varied eating disorders that get lumped together in a broad diagnostic category called, simply, “disordered eating.” It includes troublesome behaviors such as binge eating, night eating, secret eating, and food hoarding.
Eating disorders are often dismissed as being mild, even trivial, an affliction of the wealthy and privileged. However, because of their worldwide prevalence,
the World Health Organization has declared them a priority disorder. And as W. Stewart Agras, a Stanford psychiatrist, points out in
The Oxford Handbook of Eating Disorders
, eating disorders of all kinds are on the rise around the world.
In the two decades since I treated Amber, psychiatrists have learned much about who is at risk for eating disorders and what makes them susceptible. Hormonal states and brain chemistries contribute.
Because disordered eating can run in families, genetic factors are believed to play a strong role. Certain personality types are especially vulnerable. Sufferers tend to be fearful and anxious, specifically about gaining weight and being fat.
Anxiety disorders are frequently diagnosed along with anorexia nervosa. Some anorexics admit to being perfectionists or wanting to punish themselves. Many say they’re addicted—either to food or to the euphoric feeling they derive from starving.
They report enjoying exerting control over food and figure, and watching the effect their condition has on people around them. Psychiatric explanations have also
pointed to early childhood experiences and family dynamics as the cause or trigger.
Eating disorders are complex and subtle, and seemingly very human. As far as we know, other species don’t share our concerns with body image and self-worth—preoccupations that fuel human patients’ dangerous disordered eating. And a patient’s troubled social relationships and obsessions about getting fat certainly seem to be fixed in a very human matrix of culture and social pressures, media messages and memes.
However, closer inspection of veterinary data yields some surprising, overlapping eating behaviors across species. In animals, binge eating, secret eating, night eating, and food hoarding are common. Anorexia nervosa and bulimia nervosa (or close homologues of those extremes) may indeed be present in certain animals under certain stressful circumstances. And while the animal and human “psychology” of these disorders differ, neurobiologically there may be parallels. A zoobiquitous approach made me see that, like Amber, animals may also sometimes be scared to eat. In fact, for many, both wild and domestic, every meal may feel as risky as Amber’s sandwich did to her.
To understand what I mean, we have to put two very different fields of inquiry side by side. First: contemporary psychiatry and the bewildering, ill-defined, yet growing diagnosis of disordered eating. Next to it: wildlife biology and the whimsy and mishap of animals’ quest for daily bread.
A typical morning in the wilds of Yellowstone National Park might look something like this: A chipmunk pokes a whiskered nose out of her burrow and scurries over to a scattering of pinecones. With a blur of forepaws, she nibbles at several. Alone, furtively, she stuffs her cheeks, sails back to her den, and stashes the hoard in her secret underground hiding place. Then, although she has just eaten, she heads back out and approaches the food again. Ears pricked, eyes wide, she pauses. Scans her surroundings. Ignores a rustle in the leaves. She eyes the nuts. Suddenly: another crackle. This sound is different—she flees for her den, but too late.
Pounce! Swipe!
A bobcat bites down on the chipmunk’s neck and carries her limp body away.
In the tall grass nearby, unnoticed by the bobcat, crouches a silent hare—his heart revved and muscles taut for a now-unnecessary sprint to
shelter. He remains frozen for a few more moments until, sensing safety, he can resume feeding. But the patch he had been heading toward when he smelled the cat is now out of the question, too dangerous even though it’s only a few hops out of reach. Some tufts of lupine, while less nutritious, will suffice. Jaws grinding, heart racing, the hare stuffs his mouth with the easy and available vegetation.
Deep in the grass patch abandoned by the hare, a grasshopper freezes. It senses, but can’t see, a hungry spider nearby. Abruptly, the insect stops munching the protein-rich grass. Moving cautiously, it sidles over to a new plant—sugar-laden goldenrod. Its mandibles start churning rapidly on the sticky yellow flowers.
In an aspen grove on the banks of a river, elk browse in seeming calm, their twitching ears and flaring nostrils the only giveaway that stress hormones are pumping through their veins as they monitor the silent forms of a wolf pack stalking their fawns.
Under the river’s turbulent water, a juvenile cutthroat trout hides in the cleft of a rock. In the current around her drift mayfly nymphs, midges, and other nutritious morsels. But, too young and inexperienced to take on a predator in the open water, the cautious young fish stays frozen where she is, camouflaged and protected—sacrificing food for safety.
Hawks and eagles, their stomachs awash in hunger hormones, patrol overhead. Their quarry—the vigilant denizens of the gold-and-green scrub, from sagebrush lizards, partridges, and bull snakes to gophers, deer mice, and skunks—all constantly weigh a risky tradeoff. Nibble food in view of the voracious air force above—or remain hidden and go hungry?
As the sun starts to descend, the animals become even more watchful. Some, driven by hunger, are desperate to kill their calories before dark. Others shovel in food selected from their own larders or pilfered from a neighbor’s. Some animals awake with the setting sun and begin the dangerous proposition of finding food by moonlight.
One thing you can say about meals in the wild: they’re never boring. Every bite requires a life-or-death focus on two things: getting food and avoiding becoming food. If an animal cannot find and secure consistent meals, he will die of starvation. If he’s not vigilant, he will fall to predation. In nature, eating is drenched with danger, risk taking, stress, and fear.
But what if, instead of observing animals in Yellowstone, we were
peering into darkened kitchens and dining rooms, past closed office doors and tinted car windows? What if those were human animals who were scurrying, sprinting and storing, hiding and nibbling? People who were spending entire mornings in the pursuit of food, obsessing about it, changing their behavior to get or avoid it? Then the scenario might seem quite different. In fact, if exhibited by a twenty-first-century human, many of those behaviors would trouble my psychiatrist colleagues.
Today we no longer view ourselves as cowering prey. After all, we’re the most fearsome predators in the history of our planet. In civilized comfort at the top of the food chain, most of us will go through our whole lives never facing a realistic threat from a nonhuman predator. We can be grateful for that, but it obscures the fact that our DNA has a much longer memory.
In the not-too-distant past, we faced, on a daily basis, the very real threat of becoming someone’s lunch. Our genetic legacy of survival has depended on the crucial instincts our forebears developed through millions of years of evolution—the instincts that kept them alive and out of the colons of other creatures. Nowadays Volkswagen-sized eagles aren’t poised to drop on us as we exit Starbucks, soy latte in hand. But our back-stabbing office politics, our violence-drenched entertainment, even the very process of growing up can trigger physiological reactions as potent as those handed down from our animal ancestors stalked by ravenous carnivores.