Structural Racism Linked to Disparities in Adolescent Brain Development, HMS Study Finds

Harvard Medical School researchers at McLean Hospital published a study demonstrating an association between race-based adversity in childhood and structural differences in brain development.

In the February issue of the American Journal of Psychiatry, researchers Nathalie M. Durmonay, Lauren A.M. Lebois, Kerry J. Ressler, and Nathaniel G. Harnett published their findings of the correlation between childhood adversity experienced disproportionately by Black children in the U.S and differences in neurological development.

Assessing surveys from the Adolescent Brain Cognitive Development study, U.S. Census neighborhood data, and MRI scans of 1,786 Black children and 7,350 white children aged nine to 10, the team found small variations in gray matter volume in stress-related brain regions.

Harnett said in an interview Tuesday that the findings of this study stand in contrast to the myth that there are inherent neurological differences between people of different races.

“One of those folklore beliefs happens to be that individuals who are Black have smaller brains than individuals who are white,” Harnett said. "What our results really speak to is that really a significant portion of the differences between groups can really be attributed to adversities that these groups might experience differentially during childhood."

The study suggests that a key contributor to the disparity in gray matter volume between Black and white children is adversity disproportionately experienced by Black children. The researchers found that structural racism — including the likelihood of experiencing poverty, traumatic events, and family conflict — may affect differential development of the amygdala, hippocampus, and prefrontal cortex.

In addition to supporting this relationship, the study has implications for future research on the relationship between experienced adversity and post-traumatic stress disorder. When analyzing earlier PTSD research in conjunction with this study, researchers observed that Black children experienced higher severity of PTSD symptoms, and “symptom severity was further predicted by adversity,” according to the study.

“I want to understand why some people end up with PTSD,” Harnett said. “I think that the brain is probably the best way to understand that and to predict who’s likely to go on to develop it.”

This research has practical implications for doctors seeking to better understand their patients’ backgrounds.

“If we want to understand where our patients are going to end up and how well they’re going to do, we really need to understand what’s been happening in their past, and how for different patients and different individuals, those different experiences might contribute to different outcomes,” Harnett said.

In the future, this group hopes to look at the same relationship over other age groups.

“The major focus for us going forward is that we really want to know, ‘What is the trajectory of development like for individuals that are experiencing more adverse childhood events?’” he said.

Harnett hopes this will help people think about how structural racism affects future generations.

“We’re really hoping that these findings motivate people to really consider widespread structural changes to address systemic inequities, to address the traumas that people can experience in childhood,” he said.