Childhood adversity causes brain changes that occur early — around age 9 and 10 years — and disproportionately affect Black children, according to findings by Harvard Medical School researchers published in the American Journal of Psychiatry. They found that Black children in the United States are more likely to experience childhood adversity than White children, and these race-related disparities are linked to changes to brain regions associated with emotional regulation and psychiatric diseases such as posttraumatic stress disorder (PTSD).
“Our data is suggesting that what’s different between White and Black kids is not an essential, innate difference; it is the disproportionate burden of stress that we are placing on one of those groups of kids,” said senior author Nathaniel G. Harnett, PhD, director of the Neurobiology of Affective Traumatic Experiences Laboratory at McLean Hospital and assistant professor of psychiatry at Harvard Medical School. “Our research provides 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,”
“Clinicians must consider the environment their pediatric patients live in affects health status,” said Kimberly Sapre, DMSc, PA-C, CAQ-EM, who is president of the Virginia Association of Minority PAs, medical consultant for an insurtech company, and practices emergency medicine in Falls Church, Virginia. “The research shows that daily stress and trauma affect brain structure during those early developing years. The childhood adversity faced by Black children may lead to many of the psychiatric and behavioral issues clinicians will treat.” Dr Sapre was not affiliated with this study.
Large Study Cohort
Dr Harnett and colleagues analyzed a subset of data (N=9382) from the Adolescent Brain Cognitive Development (ABCD) Study, which included 7350 White children and nearly 1786 Black children in the US aged 9 to 10 years from 21 sites across the country. The data included parent and child self-reports of race and adversity-related measures, magnetic resonance imaging (MRI) brain scans, and US Census neighborhood data. Slightly more than half of the overall cohort was male (52.5%).
The researchers focused on brain regions involved in processing emotion and threat: the amygdala, hippocampus, and prefrontal cortex. Findings from previous studies have demonstrated structural changes in these brain regions in response to early exposure to adversity, the researchers explained.
Higher Rates of Adversity Found in Black Families
Traumatic events, family conflict, and material hardship were more commonly reported by Black families than White families. The rates of lower educational attainment, lower income, and unemployment were higher among parents or caregivers of Black children than White children. For example, 75% of White parents had a college degree and 66% had an income of $50,000; in comparison, 25% of Black parents had a college degree and more than half (53%) reported an income of less than $35,000.
Black children showed small but significant differences in gray matter volumes in the amygdala, hippocampus, and several subregions of the prefrontal cortex compared with White children. Almost all types of childhood adversity were uniquely linked to lower gray matter volumes in all children. Although trauma history and family conflict were not linked to lower gray matter volumes in the overall group, the authors noted that the findings do not necessarily reflect a lack of neurobiological impact from those adversities. Household income was the most common predictor of brain volume differences in the amygdala and prefrontal cortex, the study authors found.
“The differences in adversity between the groups accounted for as much as approximately 50% of the difference between the groups,” Dr Harnett said. “We indexed a fairly small number of potential adversities and at a relatively course level.”
A supplementary analysis showed that Black children in this study had significantly greater PTSD symptom severity, and that symptom severity was significantly correlated with several adversity measures (eg, parental employment, family income, family conflict, and trauma history).
Early Intervention May Mitigate the Effects of Systemic Racism
The findings raise the question of whether early intervention strategies can prevent or mitigate these brain changes found in children experiencing adversity. Dr Harnett noted that the consequences of adversity begin early, as the study found, and that many adversities are partially structural in nature. Thus, “we think that interventions need to be multifaceted: we need both individual-level approaches that can start in childhood for affected kids, but we also need to consider how we can address disparities at a systemic level,” he said.
“The effects that we saw in the study were significant, but they were quite small,” Dr Harnett explained. “We think part of this is exactly because kids are relatively resilient and at a stage where they’re going through rapid development. Our hope, then, would be that changing circumstances — reducing adversity and improving the environment — would lead to better outcomes for kids. There is ongoing work in how changing structural inequities can augment both brains and long-term health outcomes.”
The more immediate clinical implications are that clinicians “need to consider where their patients are coming from and where they’re going back to after a session,” Dr Harnett said. “Especially for those who bear a disproportionate burden of adversity, like racially minoritized kids, how are the [treatments we offer] melding with what their actual experience is like in their neighborhoods? That context is going to affect their ability to actually make the most out of their treatment.”
Limitations of the study included a lack of inclusion of other racial/ethnic groups. Lack of longitudinal MRI data was also noted as a limiting factor by the researchers. The data also do not include information on other adversity types such as nutritional differences or direct toxin exposure.
The researchers intend to build upon these findings and expand their data collection beyond the ages included in this study to track the neurobiological impact racial disparities in adversity have throughout a lifetime. They also hope to determine whether exposure to adversity may accelerate or decelerate aging in the brain and whether additional measures of adversity not included in this study may affect these regions of the brain or others involved in psychiatric disorders.
Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Dumornay NM, Lebois LAM, Ressler KJ, Harnett NG. Racial disparities in adversity during childhood and the false appearance of race-related differences in brain structure. Am J Psychiatry. 2023;180(2):127-138. doi:10.1176/appi.ajp.21090961
Racial disparities in childhood adversity linked to brain structural differences in US children. News release. McLean Hospital; February 1, 2023. Accessed February 24, 2023. https://www.mcleanhospital.org/news/racial-disparities-childhood-adversity-linked-brain-structural-differences-us-children