Besides, not all stress is bad, Bale points out. Let’s say you stress some mice. (It’s not hard to do; you can put marbles in their cages, or wet their bedding.) Let some of the stressed mice return to their mothers, but don’t let the rest go back to Mom. “There’s a big difference in how they cope in life,” says Bale. “The ones who get to go back to Mom perform better even than non-stressed animals. They get through. They pick themselves up.”
Bale is also researching the effects of a mother’s vaginal “microbiome” — the combination of bacteria inside her body — on her offspring. When a baby pushes through the birth canal, the microbiome is ingested: “That sets up the whole immune system of the baby’s gut. We think that may be why C-section babies are more prone to immune issues like asthma and allergies” — they never get exposed to that vaginal microbiome. So researchers are looking for other ways to transfer it — for instance, by taking samples from the mother and administering them to the babies orally.
Infections and changes in nutrition alter a mother’s microbiome. So does stress. In a study on mice, Bale showed that stress caused changes in the levels of a bacterium in the microbiome that’s associated with brain development. Throwing off those levels, she says, could predispose offspring to an increased risk of neurodevelopmental disorders.
But the damage caused by stress continues throughout our lifetimes. A constant bath of stress hormones “eats away” at the hippocampus, says Bale — the seat of memory. That’s why you can’t remember where you put your keys when you’re stressed. Studies show more methylation of the genes in the hippocampi of those who commit suicide than in the hippocampi of people who die suddenly of other causes. Bale just landed a grant for a new study of women who have experienced stressful early life events like sexual abuse; such women are more likely to develop affective disorders such as depression, eating disorders and ADHD. “We’re following these women as they get pregnant,” Bale says, “to see about their children.”
Not everyone who experiences trauma develops a disorder, of course. Animal research shows that a doting mother gives you a better chance of coming through unscathed. What is it that a good mom passes on to her offspring that helps them cope?
It could be as simple as self-confidence. How much control you feel you have impacts the effects of stress. Put a rat in a cage, deliver electrical shocks, and train it to press a lever to avoid the shocks. If you then take away the lever, the animal’s stress shoots through the roof. If you give back the lever but it doesn’t affect the shocks — if it’s not even connected to anything — the rat’s stress response still goes down, simply because it’s there . Believing you’re the master of your fate builds resiliency.
But you know what else makes a big difference? Socioeconomic status. Those at the top of society’s ladder have more resources with which to come at problems. And the stresses of poverty may account for the shorter life spans of the poor, as well as their high rates of stress-related illnesses like depression, diabetes and heart disease. Penn neuroscientist Martha Farah has mapped the socioeconomic status of children against their ability to pay attention and tune out distractions in school. Her findings: The rich don’t just have more money; their brains are better able to learn.
I find it stressful to think that a child’s ability to cope with stress may be dictated by how stressed her parents were at the time she was conceived. When I mention this to Michael Baime, he shrugs: “Some people are just born anxious. Some are born happy. Some are born depressed. Some of us are born good-looking. Life isn’t fair.”
CLEARLY, STRESS IS SERIOUS STUFF. But it’s also a sort of badge of honor: “God, I’m so busy!” “I have so much to do!” Who isn’t stressed? Babies. Retirees. Bums. Look at the latest list of the most stressful jobs: airline pilot, military general, senior corporate executive. Least stressful? Librarian and audiologist. Which camp would you rather be in?
As Michael Baime says, “If you look at the relationship between stress and performance, it’s a rising curve: As stress increases, your performance increases” — right up to the point where you tumble over the edge.