your heart rate and blood pressure to elevate. But the HPA axis can’t distinguish between different types of threat, so it activates every defense, all at once, in response to any threat. Unfortunately, this means you often experience stress responses that are not at all helpful—like when you need to speak before an audience, and suddenly your mouth goes dry. Your HPA axis, sensing danger, is conserving fluids, preparing to ward off an attack. And you’re standing there looking for a glass of water and swallowing hard.
Think of the HPA axis as a superdeluxe firehouse with a fleet of fancy, high-tech trucks, each with its own set of highly specialized tools and its own team of expertly trained firefighters. When the alarm bell rings, the firefighters don’t take the time to analyze exactly what the problem is and figure out which truck might be most appropriate. Instead, all the trucks rush off to the fire together at top speed, sirens blaring. Like the HPA axis, they simply respond quickly with every tool they might need. This may be the right strategy for saving lives in fires, but it can also result in a dozen trucks pulling up to put out a single smoldering trash can—or worse, responding to a false alarm.
5. Scared to Death
Nadine Burke Harris saw the results of this firehouse effect in her patients all the time. One day at the Bayview clinic, she introduced me to one of them, a teenager named Monisha Sullivan who had first come to the clinic when she was sixteen and a new mother. Monisha’s childhood was about as stressful as they come: She was abandoned just a few days after she was born by her mother, who was a heavy user of crack cocaine and other drugs. As a child, Monisha lived with her father and her older brother in a section of Hunters Point with a lot of gang violence until her father, too, got lost in a drug habit; when Monisha was ten, she and her brother were removed from their home by the city’s child protection bureau, separated from each other, and placed in foster care. Ever since, she had been ricocheting through the system, staying for a week or a month or a year in each foster or group home until, inevitably, tensions escalated over food or homework or TV, and she ran away or her caregivers gave up. Then it was on to another placement. In the previous six years, she had cycled through nine different homes.
When I met Monisha, in the fall of 2010, she had just turned eighteen, and three days earlier, she had been emancipated from the foster-care system in which she had spent almost half her life. Her most painful experience, she told me, was the day she was placed in foster care. Without any warning, she was pulled out of class by a social worker she had never met and driven to a strange new home. It was months before she was able to have any contact with her father. “I remember the first day like it was yesterday,” she told me. “Every detail. I still have dreams about it. I feel like I’m going to be damaged forever.”
As we sat in the therapy room at the clinic, I asked Monisha to describe for me what that damage felt like. She is unusually articulate about her emotional state—when she feels sad or depressed, she writes poems—and she enumerated her symptoms with precision. She had insomnia and nightmares, she said, and at times her body inexplicably ached. Her hands sometimes trembled uncontrollably. Her hair had recently started falling out, and she was wearing a pale green headscarf to cover up a thin patch. More than anything, she felt anxious: anxious about school, anxious about her young daughter, anxious about earthquakes. “I think about the weirdest things,” she said. “I think about the world ending. If a plane flies over me, I think they’re going to drop a bomb. I think about my dad dying. If I lose him, I don’t know what I’m going to do.” She was even anxious about her anxiety. “When I get scared, I start shaking,” she said. “My heart starts beating. I start sweating. You know how people say ‘I was scared to death’? I get scared that that’s really going to happen to me one day.”
The firehouse metaphor might help us understand what was happening with Monisha Sullivan. When she was a child, her fire alarm went off constantly, at top volume:
When McEwen first proposed the notion of allostatic load, in the 1990s, he didn’t conceive of it as an actual numerical index. But recently, he and other researchers, led by Teresa Seeman, a gerontologist at UCLA, have been trying to “operationalize” allostatic load, to produce a single number for each individual that would express the damage that a lifetime of stress management had imposed. Doctors use comparable biological-risk indicators all the time today, most notably blood pressure measurements. Those numbers are obviously useful as predictors of certain medical conditions (which is why your doctor takes your blood pressure every time you visit his or her office, no matter what ailment you might be there for). The problem is, blood pressure readings alone are not precise measures of future health risks. A more accurate allostatic-load index would include not just blood pressure and heart rate but other stress-sensitive measures: levels of cholesterol and high-sensitivity C-reactive protein (a leading marker for cardiovascular disease); readings of cortisol and other stress hormones in the urine and of glucose and insulin and lipids in the bloodstream. Seeman and McEwen have shown that a complex index including all those values would be a much more reliable indicator of future medical risk than blood pressure or any other single-factor measure in use today.
It’s an attractive and fascinating notion, and a slightly frightening one: a single number that a doctor could give you in, say, your early twenties that would reflect both the stress you had experienced in life to that point and the medical risks that you now faced as a result of that stress. In some ways it would be a more refined version of your ACE score. But unlike your ACE score, which relies on your own report of your childhood, your allostatic-load number would reflect nothing but cold, hard medical data: the actual physical effects of childhood adversity, written on your body, deep under your skin.
6. Executive Functions
As a medical doctor, Burke Harris was initially interested in the physiological effects that early trauma and unmanaged stress had on her patients: Monisha’s trembling hands and hair loss and unexplained pains. But Burke Harris quickly realized that these forces had an equally serious impact in other aspects of her patients’ lives. When she used a modified version of the Felitti-Anda ACE questionnaire with more than seven hundred patients at her clinic, she found a disturbingly powerful correlation between ACE scores and problems in school. Among her patients with an ACE score of 0, just 3 percent had been identified as having learning or behavioral problems. Among patients with an ACE score of 4 or higher, the figure was 51 percent.
Stress physiologists have found a biological explanation for this phenomenon as well. The part of the brain most affected by early stress is the prefrontal cortex, which is critical in self-regulatory activities of all kinds, both emotional and cognitive. As a result, children who grow up in stressful environments generally find it harder to concentrate, harder to sit still, harder to rebound from disappointments, and harder to follow directions. And that has a direct effect on their performance in school. When you’re overwhelmed by uncontrollable impulses and distracted by negative feelings, it’s hard to learn the alphabet. And in fact, when kindergarten teachers are surveyed about their students, they say that the biggest problem they face is not children who don’t know their letters and numbers; it is kids who don’t know how to manage their tempers or calm themselves down after a provocation. In one national survey, 46 percent of kindergarten teachers said that at least half the kids in their class had problems following directions. In another study, Head Start teachers reported that more than a quarter of their students exhibited serious self-control-related negative behaviors, such as kicking or threatening other students, at least once a week.
Some of the effects of stress on the prefrontal cortex can best be categorized as emotional, or psychological: anxiety and depression of all kinds. I kept in touch with Monisha in the months after our first meeting, and I saw a lot of those emotional symptoms in her. She was plagued by self-doubt—about her weight, her parenting ability, her prospects in general. She was assaulted one night by an ex-boyfriend, a sketchy character she had invited over, against her better judgment, to stave off her loneliness. And she struggled constantly to cope with a flood of
