- Researchers say racial inequities can produce poverty and trauma that can lead to changes in the brain structure of children.
- They say these changes can bring on conditions such as post-traumatic stress disorder.
- They say their findings should dispel any notions that there are fundamental differences in the brains of people of different ethnicities.
Black children in the United States are more likely than white children to be exposed to toxic stressors such as poverty and hardship.
That adversity can affect their brain structure as well as lead to conditions such as post-traumatic stress disorder (PTSD).
That’s according to a study published today in the American Journal of Psychiatry.
Researchers at the McLean Hospital in Massachusetts looked at data from the Adolescent Brain and Cognitive Development (ABCD) study, the largest long-term study of brain development and child health in the U.S.
In their research, they analyzed the MRI brain scans of more than 7,300 white children and nearly 1,800 Black children, all ages 9 and 10.
The researchers reported that the Black children had small neurological differences or lower gray matter volumes in multiple areas of the brain when compared with white children.
They also discovered that experiencing adversity was the significant differentiating factor. Household income was the most common predictor of brain volume differences.
Nathaniel G. Harnett, Ph.D. led the study.
He is the director of the Neurobiology of Affective Traumatic Experiences Laboratory at McLean Hospital. He’s also an assistant professor of psychiatry at Harvard Medical School in Massachusetts.
“Largely what we saw is that in regions of the prefrontal cortex, the hippocampus, and amygdala… white children actually had larger regions than Black children did. And when we actually looked at the demographics of these kids, we saw really striking differences, too,” Harnett told Healthline.
He says those regions of the brain regulate our response to fear and threats. Experts believe those areas are involved in PTSD and other stress-related disorders.
“The Black children came from more disadvantaged neighborhoods. The parents and caregivers were more unemployed, had less education, and were going through more hardship,” Harnett said.
“I want to highlight that we are seeing differences in the size of these different regions, but they’re not like massive differences, right?” he added. “They’re small, but we think they’re going to be significant for how these kids are going to develop later on in life.”
Harnett said the findings should contradict some commonly held beliefs that there are race-related differences in the brain.
“There’s this sort of colloquial view that Black and white people have different brains,” he explained. “When you do brain scans, you’ll sometimes see differences in how the brain responds to different stimuli, or there might be differences in the size of different brain regions.”
“But we don’t think that’s due to skin color. We don’t think white people have just categorically different brains than Black people. We really think it’s due to the different experiences these groups have,” he said.
“It is resonant with a bunch of other studies that have looked at the effects of adversity on brain development. So that’s not really a surprising finding,” said Dr. Joan Luby, a professor of child psychiatry at Washington University School of Medicine in St. Louis.
“There are lots of different studies in smaller samples but are more deeply phenotyped than the ABCD Study that clearly show the negative impacts of adversity on brain development, even beginning in utero,” she told Healthline.
Luby and Deanna M. Barch, Ph.D., a professor of psychiatry at Washington University’s Department of Psychological and Brain Sciences, co-authored an editorial about the study.
They took issue with the way the findings are characterized.
“What we sort of object to is the whole conceptualization of a race-based distinction,” Luby said.
“I think that what the literature really shows is that the negative effects have to do with experiences of trauma, like poverty, experiences of discrimination, and institutional racism,” she explained. “And the idea that a distinction is made based on race, which is a social construct, we don’t think is the appropriate way to look at this. And it’s very, very misleading to look at it in that way.”
“We think that we can make inferences about these findings that are specific to experiences of adversity, not experiences of race,” said Luby.
The study’s researchers say they worry that because the children had those brain changes so early, it might put them at risk for PTSD or some other psychiatric disorders.
“These kids are nine, right? They didn’t get to choose where they grew up. They didn’t get to choose where their parents settled or what their parents did. They have no choice in any of those, and yet we’re asking them to shoulder all of these burdens. And it’s impacting their brain in a way that really may have severe consequences for them later on down the line,” Harnett said.
The ABCD study is ongoing with the participants getting a brain scan every two years.
Harnett says there are other areas the researchers can continue to learn about those brain changes and how they may affect the children as they get older.
But he says their current findings ought to send a message.
“So it’s for clinicians, researchers, people in public policy who really care about the health and wellbeing of their constituents” he explained. “This stress has a real impact on the brains of our children. And if we don’t take that seriously, it’s going affect them.”