Black children in the United States are more likely to experience childhood adversity than white children, and these disparities are reflected in differential changes to regions of the brain linked to psychiatric diseases like post-traumatic stress disorder (PTSD), according to new research led by McLean Hospital, a member of Mass General Brigham.
The findings, published in the American Journal of Psychiatry, suggest that adversity may act as a toxic stressor to regions of the brain related to threat processing and that this exposure is disproportionately seen in Black children.
The authors added that their study provides additional evidence contradicting the pseudoscientific falsehood that there are inherent race-related differences found in the brain and instead emphasizes the role of adversity brought on by structural racism.
For the study, led by Nathaniel G. Harnett, PhD, director of the Neurobiology of Affective Traumatic Experiences Laboratory at McLean Hospital, researchers analyzed surveys and MRI brain scans of more than 7,300 white children and nearly 1,800 Black children in the U.S. who were 9 and 10 years old.
They found Black children displayed small neurobiological differences reflected as lower gray matter volumes in the amygdala, hippocampus, and prefrontal cortex compared with white children. Their analysis also revealed that experiencing adversity was the significant differentiating factor, with household income the most common predictor of brain volume differences.
“Our research provides substantial evidence of the effects structural racism can have on a child’s developing brain, and these small differences may be meaningful for their mental health and well-being through adulthood,” said Harnett, who is also an assistant professor of psychiatry at Harvard Medical School.
“The dataset in our study included children younger than 10 years old—children who have no choice in where they are born, who their parents, are and how much adversity they are exposed to. These findings offer another chilling reminder of the public health impact of structural racism, and how crucial it is to address these disparities in a meaningful way.”
Mining Data for Social Determinants of Adversity and Impact on Brain
In the U.S., there are stark racial disparities in the distribution of economic resources, exposure to stress, and psychiatric disorder prevalence. To date, limited research has investigated how racial inequities in the social determinants of health may lead to changes in the brain for different groups.
This led Harnett and colleagues at McLean’s Neurobiology of Fear Laboratory to leverage strong datasets to look for potential race-related differences in the neurobiology of psychiatric disorders and how racial structural inequities may explain these differences.
The researchers reviewed data from the 2019 Adolescent Brain and Cognitive Development (ABCD) Study, a large-scale MRI research effort that included nearly 12,000 U.S. children between the ages of 9 and 10 from 21 sites across the country.