July 26

A Neuroscience Perspective on the Lifelong Consequences of Detaining Kids at the Border

[En español]

If you’ve been even partially tuned in to the news over the last few months, you’ve heard about the gut-wrenching separation of children from their parents at the United States border and the detainment centers where these children have been held.


“Sometimes by losing a battle you find a new way to win the war.”  — Quote from Donald Trump’s 1987 book The Art of the Deal, displayed on a mural of the president at a Brownsville, Texas detainment center in which over 1,500 immigrant children were held after being separated from their parents at the U.S.-Mexico border.

You may have seen pictures of young kids in cages, been watching when Rachel Maddow broke down reading the headline “Trump administration officials have been sending babies and other young children forcibly separated from their parents to at least three ‘tender age’ shelters in South Texas,” or seen the emotional impact on politicians like Senator Elizabeth Warren when they visited these centers for themselves. You may have even tuned in when Melania Trump stated that detained children were “in this situation as a direct result of adult actions,” placing blame on parents trying to protect their families by escaping a dire situation in their home country –something likely unfathomable to most of us. 

The world continues to tune in as children, many visibly in a state of confusion, are reunited with their parents and testimonies are released.

[My son] is not the same since we were reunited. I thought that, because he is so young he would not be traumatized by this experience, but he does not separate from me. He cries when he does not see me. That behavior is not normal. In El Salvador he would stay with his dad or my sister and not cry. Now he cries for fear of being alone.

–Testimony from mother Olivia Caceres, who was separated from her 1-year-old son for 85 days, reported by PBS NewsHour on July 5th.

Many families are still waiting to be reunited.

Although there has been some recent successful legal opposition to Trump’s immigration agenda—on July 9th a Federal District Court Judge in Los Angeles ruled against changing a long-standing detainment law, and on July 16th the immediate deportation of reunited families was halted temporarily—these children have already experienced the shock of being torn from their parents and left in a foreign environment indefinitely. Trauma of that severity does not just dissipate upon reunion.

The Early (Less Ethical) Days of Childhood Separation Research


Wire and cloth surrogate mothers. “Affectional responses in the Infant Monkey.” Science, 1959.

One of the first researchers to study the importance of mother-offspring bonding was Dr. Harry Harlow who, starting in the 1950s, used rhesus macaques (a species of Old World monkeys) for a number of—now deemed highly unethical—experiments. Harlow separated newborn macaques from their mothers, replacing the actual mother with two artificial surrogate mothers: one made of wire with a bottle to feed the baby and one made of cloth but without food. The baby macaques spent far more time with the cloth mother, cuddling against it (particularly in more stressful situations), only turning to the wire mother when hungry, indicating that the mother-offspring bond goes beyond the physiological need of food.


A rhesus macaques infant left without its mother or artificial surrogate freezes in a crouched position. “Affectional responses in the Infant Monkey.” Science, 1959.

Harlow also performed a series of isolation experiments and found that monkeys left without a mother or artificial surrogate (for 3, 6, or 12 months) never fully recovered socially. At the end of isolation, many of those monkeys went into what was described as “emotional shock,” characterized by self-clutching and rocking back and forth. In one case, a monkey refused to eat and died shortly after release.  

Over the last couple of decades an increasing amount of research has been done to investigate the impact of elevated levels of stress during childhood, and the results have been nothing short of bleak. If anything, they have provided an even greater incentive for public concern regarding the actions of this presidency.  

Orphans of the Romanian Revolution

In the late 1990s, researchers began studying the development of children who were left in orphanages following the overthrow of the Romanian government in 1989. Children were often left for many hours, sometimes days, in their cribs, deprived of human interaction. In a study published in 2012, a research team led Dr. Charles Nelson of Harvard University found that this early childhood seclusion not only affected the morphology of these children’s brains, but also the activity. Based on magnetic resonance imaging (MRI), these children showed a huge reduction in gray and white matter. Outside of the wide range of neurological consequences that stem from this reduction, the brains of these children were also physically smaller. Nelson and his team also used electroencephalography (EEG) to measure electrical activity in the brains of these children and found a severe decrease in brain activity, suggesting issues with processing information.

The Establishment of ACEs

In 1998, a team led by Dr. Vincent Felitti at Kaiser and Dr. Bob Anda at the CDC was the first to study the long-term effects of childhood trauma in a large population. Through a survey of over 9,000 participants they were able to study seven categories of adverse childhood experiences (ACEs): psychological abuse, physical abuse, sexual abuse, violence against mother, and living in a household with members who were substance abusers, mentally ill/suicidal, or even imprisoned. ACE scores (0-7) were assigned based on how many of those categories applied to a participant and then that score was compared to risky behaviors in adulthood. The researchers adjusted for the effect of demographic factors as well as the risk factors leading to early death and the association between the cumulative number of categories and childhood exposures.

Over half of participants had an ACE score of at least 1, and 25% of participants had an ACE score of at least 2. They found that participants with ACE scores of 4 or higher, compared to those with an ACE score of 0, had anywhere from a 4- to 12-fold increased risk for alcoholism, drug abuse, depression, and suicide attempt. They also showed a highly significant increase in risky sexual behaviors, which led to a higher incidence of sexually transmitted disease. The team also discovered a significant relationship between ACE scores and developing ischemic heart disease, cancer, severe obesity, chronic lung disease, skeletal fractures and liver disease.

This work made it clear that early childhood trauma leads to an increased risk of disease (beyond the brain) throughout an entire lifetime. It also spawned dozens of studies to understand, at the molecular level, what leads to this risk.

Childhood Trauma Leads to Increased Disease Risk, Regardless of Risky Decision Making

Initially, however, this work was met with some pushback. As pediatrician Dr. Nadine Burke Harris recounted in her 2014 TEDMED talk on the long-term impact of childhood trauma, “Some people looked at this data and they said, ‘Come on. You have a rough childhood, you’re more likely to drink and smoke and do all these things that are going to ruin your health. This isn’t science. This is just bad behavior.’”

So, is an increased disease risk just the result of risky behavior? No.

“It turns out this is exactly where the science comes in,” said Harris, whose career trajectory changed once she discovered the work of Felitti and Anda and began looking at childhood trauma as both a social and mental health issue. “We now understand better than we ever have before how exposure to early adversity affects the developing brains and bodies of children.”

Trauma, Chronic Stress and “Fight-or-Flight”

So, what do all of these adverse childhood experiences have in common? Stress.

During a stressful event your amygdala sends a signal to your hypothalamus, a controller of your autonomic nervous system (ANS) and pituitary. The hypothalamus is often described as the brain’s control center, regulating involuntary bodily functions like heartbeat and breathing. Upon activation, the hypothalamus begins sending signals to the adrenal glands which then begin producing adrenaline. This flux of adrenaline then triggers the sympathetic nervous system–the branch of the ANS controlling the “fight-or-flight” response.

Someone undergoing this response will experience an elevation in heart rate, increased pupil dilation, rapid breathing and a sharpening of senses like vision, as blood begins to pump away from the gut and toward more vital areas, for instance leg muscles, all in preparation for having to engage (fight) or quickly get away (flight).

Once the initial adrenaline surge is over, the hypothalamus-pituitary-adrenal (HPA) axis takes over, keeping the fight-or-flight response going as long as danger is perceived. The hypothalamus releases corticotropin-releasing hormone (CRH), which then triggers release of adrenocorticotropic hormone (ACTH) by the pituitary. ACTH then travels to the pituitary, causing the release of cortisol. Cortisol levels stay elevated until a stressful situation is over. In the case of chronic stress, the HPA axis stays activated, causing the level of multiple hormones, including epinephrine and cortisol, to remain high. The elevation in these hormones has been shown to have detrimental effects, including increased risk of stroke and heart attack.

Research is ongoing to understand how childhood trauma can not only affect different regions of the brain, but also overall gene expression. Researchers in the epigenetic community believe that chronic stress can affect DNA methylation, based on data showing that, in subjects who have undergone traumatic experiences, DNA methylation is altered in specific regulatory sites within well-established stress-processing genes.

So, how does that relate back to the detainment of immigrant children? Without their parents, they’re at a higher risk for chronic stress and thereby its long-term implications.

“Particularly for children, one of the most important factors is having a nurturing caregiver who the child trusts — that actually helps to support the child to biologically turn off that biological stress response,” said Harris, in a recent interview with Dara Lind of Vox.

Where do we go from here?

As detained children are subjected to genetic testing to ensure that they are being returned to their rightful parents and not at risk of being taken for human trafficking, as kids and their parents are sent back to a dire situation in the country their parents fled from, and as questions still loom as to whether or not some children will ever reunite with their families, what can we, the general public, do?

According to Harris, we can create more public awareness surrounding childhood trauma and its lasting effect on individuals and societies as a whole. The more people who are involved, the greater the chance of creating a call to action to address the long-term impact of childhood trauma like we would other diseases that have plagued our country (HIV/AIDS, diabetes, cancer, etc.).

She believes that recognizing childhood trauma as a public health crisis will allow researchers, doctors, and lawmakers to take action. In her own words, “This is treatable. This is beatable. The single most important thing that we need today is the courage to look this problem in the face and say, this is real and this is all of us. I believe that we are the movement.”

If you would like to learn more and/or are interested in donating to the Center for Youth Wellness, a center created by Dr. Harris and colleagues to prevent, screen and treat the impact of adverse childhood experiences, please visit: https://centerforyouthwellness.org.


Samantha Jones, PhD, is a former UCSD Biomedical Sciences graduate student. She recently moved to Washington D.C. to begin a position as a Production Editor for Chemical & Engineering News.