The Deepest Well: Healing the Long-Term Effects of Childhood Trauma and Adversity—A Transformative Guide to Understanding Childhood Trauma and Health

by Nadine Burke Harris

Twenty years of medical research has shown that childhood adversity literally gets under our skin, changing people in ways that can endure in their bodies for decades. It can tip a child’s developmental trajectory and affect physiology. It can trigger chronic inflammation and hormonal changes that can last a lifetime. It can alter the way DNA is read and how cells replicate, and it can dramatically increase the risk for heart disease, stroke, cancer, diabetes—even Alzheimer’s.

most of my patients’ ADHD symptoms didn’t just come out of the blue. They seemed to occur at the highest rates in patients who were struggling with some type of life disruption or trauma,

Working with patients for over two decades had taught him that on the other side of a pregnant pause was usually the diagnostic gold.

Fast-forward a few decades; Patty’s sudden weight gain coincided with being hit on by her patient. Felitti wondered if she might be subconsciously protecting herself from what must have seemed like a recurring trauma by gaining weight.

the higher a person’s ACE score, the greater the risk to his or her health. For instance, a person with four or more ACEs was twice as likely to develop heart disease and cancer and three and a half times as likely to develop chronic obstructive pulmonary disease (COPD) as a person with zero ACEs.

The body of research sparked by the ACE Study makes it clear that adverse childhood experiences in and of themselves are a risk factor for many of the most common and serious diseases in the United States (and worldwide), regardless of income or race or access to care.

The ACE Study strongly establishes a dose-response relationship, which is an important step toward demonstrating causality. A person with an ACE score of seven or more has triple the lifetime odds of getting lung cancer and three and a half times the odds of having ischemic heart disease, the number one killer in the United States.

It turned out that “bad behavior” accounted for only about 50 percent of increased likelihood for disease. In a way that’s good news, because it means that if a person is exposed to ACEs and he is careful to avoid smoking, physical inactivity, and other health-damaging behaviors, he can protect himself from about 50 percent of the health risk.

The problem with PTSD is that it becomes entrenched; the stress response is caught in the past, stuck on repeat.

The body senses danger, and it sets off a firestorm of chemical reactions aimed to protect itself. But most important, the body remembers.

What makes the stress response of a child with zero ACEs different from Diego’s stress response is a complicated question that we will begin to unravel, but it all starts with the same system. When it’s in good working order, it can help save your life, but when it’s out of balance, it can shorten it.

Once you do get away and are back in the safety of your cave, both the SAM and the HPA axes are designed to shut themselves down. The body uses a sort of stress thermostat called feedback inhibition that triggers the stress response to turn itself off once it has done its job. High levels of adrenaline and cortisol feed back to the parts of the brain that initiate the stress response and turn them off. What an incredibly evolved system! Especially if you live in a forest and there are bears. But what happens when you can’t experience safety in your cave because the bear is living in the cave with you?

But for every ACE a child has, the risk of tolerable stress tipping over into toxic stress increases, as the system responds more frequently and intensely to multiple stressors.

children are particularly sensitive to repeated stress activation. High doses of adversity affect not only the brain structure and function but also the developing immune system and hormonal systems, and even the way DNA is read and transcribed. Once the stress-response system gets wired into a dysregulated pattern, the biological effects ripple out, causing problems within individual organ systems. Because the body is like one big, intricate Swiss watch, what happens in your immune system is deeply connected to what happens in your cardiovascular system.

this natural stress-response provocation challenge gave us an opportunity to test the second, equally important ingredient for toxic stress—the caregiver’s ability to act as a buffer. The kids who had the worst responses were also the ones whose caregivers were the least likely to hug, kiss, sing to, or otherwise soothe their child. We heard a lot of “Hold him down!” and “I don’t have time for this, I have to be back at work in a half hour.”

When you put a kid who had experienced adversity in an MRI machine, you could see measurable changes to the brain structures.

They found that the more symptoms a kid had, the higher his cortisol levels were and the smaller the volume of his hippocampus. After the first measurement of the hippocampus, they measured the same kids again twelve to eighteen months later and found their hippocampi were even smaller. Despite the fact that these kids were no longer experiencing trauma, the parts of their brains responsible for learning and memory were still shrinking, showing us that the effects of earlier stress were still acting on the neurological system.

We decided our focus would be on the association between ACE scores and two of the most common issues I saw in my patients: obesity and learning/behavior problems.

profound aching in my heart for all the kids who were struggling in school but being told that they had ADHD or a “behavior problem” when these problems were directly correlated with toxic doses of adversity.

Part of the problem has been that, unlike ADHD, the diagnosis of toxic stress doesn’t yet exist in the medical literature.

For a patient with a high ACE score, it may not be the obesity that shortens his or her life but the underlying toxic stress that the obesity is signaling.

if a patient had four or more ACEs, she was thirty-two times as likely to have learning or behavior problems, which suggested that the underlying issue was probably not ordinary ADHD. In those cases, I was convinced that the problem was chronic dysregulation of the stress-response system, which inhibited the prefrontal cortex, overstimulated the amygdala, and short-circuited the stress thermostat—in other words, toxic stress.

Based on the results of our chart review, it seemed that learning was the proverbial canary in the coal mine. The fact that our patients with four or more ACEs were 32.6 times as likely to have been diagnosed with learning and behavioral problems signaled to us that ACEs had an outsize effect on children’s rapidly developing brains.

I understood that a child’s brain forms more than one million neural connections every second during the first years of life. I’d also seen firsthand during my medical residency that if that process got disrupted, by a toxin, a disease, or even physical trauma, the consequences could be serious.

For kids with toxic stress, the activity of the prefrontal cortex is inhibited in two ways. First, the overactive amygdala sends messages to the PFC telling it to decrease its functioning because something scary is happening; you don’t want reason getting in the way of survival. The second is that the locus coeruleus is flooding the brain with noradrenaline, compromising the ability to override instincts and impulses. The PFC is the part of the kid’s brain that puts the brakes on impulses and helps him or her make smarter decisions. Telling a kid to sit still, concentrate, and ignore stimuli that are flooding his brain with the need to act is a lot to ask. This down-regulation of the PFC can have different consequences for different people. For some, it results in an inability to concentrate and solve problems, but in others it manifests as impulsive behavior and aggression.

The ACE Study shows that there is a dose-response relationship between ACE exposure and engaging in many activities and substances that activate the VTA. A person with four or more ACEs is two and a half times as likely to smoke, five and a half times as likely to be dependent on alcohol, and ten times as likely to use intravenous drugs as a person with zero ACEs. So for anyone looking to prevent young folks from developing dependencies on bad-for-you dopamine stimulators like cigarettes and alcohol, understanding that exposure to early adversity affects the way dopamine functions in the brain is an absolute must.

Obesity is a much more familiar foe, but in the hormonal system, we see the double whammy. As I mentioned above, because of its impact on the pleasure center (the VTA), chronic stress increases your cravings for high-sugar, high-fat foods, and elevated cortisol makes it harder for your body to metabolize sugars and easier for your body to store fat.

Chronic exposure to stress hormones can suppress the immune system in some ways and activate it in others, and unfortunately none of it’s good. Stress can lead to deficiency in the part of the immune system that fights off the common cold, tuberculosis, and certain tumors.

Every second in the first years of life over one million new neural connections are formed, so if an infant isn’t getting enough fats and proteins needed to make healthy brain connections, that can have significant impacts.

But if an infant doesn’t have a caregiver’s reciprocal eye contact, stimulating facial expressions, snuggles, and kisses, hormonal and neurologic damage can occur, and that can prevent a child from growing and developing normally. When a baby is not being cared for, she doesn’t grow well, even if she has enough nutrition.

They found that pups of high-licker moms had lower levels of stress hormones, including corticosterone, when they were handled by researchers or otherwise stressed out. This high-licker-leads-to-low-stress effect also showed a dose-response pattern: the more licking and grooming the rat pups got, the lower their levels of stress hormones. In addition, the pups of high-licker moms had a more sensitive and effective “stress thermostat.” By contrast, pups of low lickers not only had higher spikes of corticosterone in response to a stressor (in this case, being placed in restraints for twenty minutes), they also had a harder time shutting off their stress response than did the pups of high-licker moms.

The licking and grooming behavior that occurred in the pups’ first ten days of life predicted changes to their stress response that lasted for the entire lifetime. Even more startling, the changes continued into the next generation, because female pups who had high-licker moms became high lickers themselves when they had their own kids.

epigenetic regulation and it’s critical to our understanding of why toxic stress is so damaging to our lifelong health. When a four-year-old breaks a bone, that trauma is not encoded in his epigenome; it doesn’t affect him in the long term. But when a four-year-old experiences chronic stress and adversity, some genes that regulate how the brain, immune system, and hormonal systems respond to stress get turned on and others get turned off, and unless there is some intervention, they’ll stay that way, changing the way the child’s body works and, in some cases, leading to disease and early death.

Meaney and his team found that high-licker moms were releasing high levels of serotonin in their offspring. You may have heard that serotonin is the body’s natural antidepressant. It boosts mood and acts as the equivalent of rat-pup Prozac. This serotonin didn’t just make the pups feel better, it also activated a chemical process that changed the transcription of the part of the DNA that regulates the stress response. Meaney and colleagues eventually demonstrated that all that licking and grooming ultimately changed the epigenetic markers on the rat pups’ DNA, leading to lifelong changes in the stress response.

stress had a major impact on the length and health of telomeres, and that in turn had a major impact on the risk of disease.

a focus on the underlying biology of toxic stress and the factors that helped balance the dysregulated pathways—sleep, integrated mental-health services, and healthy relationships—made a big difference for our patients.

moving our bodies builds our brains as well as our muscles. When it comes to combating toxic stress, addressing the dysregulated immune system is as important as supporting brain function. Regular exercise has also been shown to help regulate the stress response and reduce the presence of inflammatory cytokines.

For a person with toxic stress, moderate physical activity (like breaking a sweat for roughly an hour a day) can help the body better decide which fights to pick and which ones to walk away from.

We saw that exercising made a huge difference for our kids, but so did eating right. Making a few specific changes to what grade of fuel went in the tank (e.g., substituting lean proteins and complex carbohydrates for greasy fast food) improved the body’s ability to regulate itself. We explained that exercising and eating healthfully not only contributed to weight loss but also helped boost the immune system and improve brain function.

Eating foods that are high in omega-3 fatty acids, antioxidants, and the fiber from fruits, vegetables, and whole grains helps fight inflammation and bring the immune system back into balance.

At that point, my staff and I had some strong strategies for specifically targeting and healing the dysregulated stress response: sleep, mental health, healthy relationships, exercise, and nutrition. Not surprisingly, these are the same things that, as Elizabeth Blackburn and Elissa Epel’s research showed, boost levels of telomerase (the enzyme that helps to rebuild shortened telomeres).

Other studies have shown that meditation decreases cortisol levels, enhances healthy sleep, improves immune function, and decreases inflammation—all critical parts of keeping our biological systems balanced and able to mitigate the effects of toxic stress.

Mind Body Awareness (MBA) Project. MBA was doing mindfulness work (both meditation and yoga) with kids in juvenile hall and getting some solid results.

Sleep, mental health, healthy relationships, exercise, nutrition, and mindfulness—we saw in our patients that these six things were critical for healing. As important, the literature provided evidence of why these things were effective. Fundamentally, they all targeted the underlying biological mechanism—a dysregulated stress-response system and the neurologic, endocrine, and immune disruptions that ensued.