Adversity in childhood linked to accelerated brain development

A new study published in Molecular Psychiatry suggests that adversity experienced during late childhood is associated with accelerated changes in brain connectivity between cortical and subcortical regions. These neural changes may help protect against the development of internalizing symptoms, such as anxiety or depression, but they are also associated with lower academic performance. The findings highlight how brain responses to stress may support emotional coping while potentially undermining other aspects of functioning.

Previous studies have shown that early life stress is linked to long-term changes in the brain, including alterations in connectivity between regions involved in emotion regulation and cognitive control. However, it has been difficult to separate the effects of adversity from other factors such as socioeconomic status, genetic risk, or environmental instability. To overcome this, the researchers used a statistical technique known as propensity score weighting, which allowed them to adjust for hundreds of potential confounding variables.

The research drew on data from the Adolescent Brain Cognitive Development (ABCD) Study, a large, ongoing project tracking the brain and behavioral development of thousands of children in the United States. For this analysis, the team focused on 7,190 children who had completed resting-state brain scans at both baseline (around age 10) and two years later. They calculated changes in the strength of connections between different brain networks and between cortical networks and subcortical structures like the amygdala, hippocampus, and striatum. The children also reported adverse life events that occurred during the two-year period, such as family conflict, illness, or moving homes.

To reduce bias, the researchers first used machine learning to calculate how likely each child was to experience adverse events based on 390 background variables, including age, sex, race, prior adversity, family income, parental mental health, and baseline brain data. These probabilities were used to create weights that balanced the sample, mimicking a randomized experimental design. The team then applied a method called elastic net regression to predict the number of adverse events a child experienced based on their brain connectivity changes.

In both the training group and an independent testing group, the researchers found that patterns of brain development predicted the number of adverse events experienced, even after adjusting for confounding factors. The strongest patterns involved decreases in functional connectivity between large-scale cortical networks and subcortical regions. These decreases were most prominent in connections involving the cingulo-opercular and sensorimotor networks, suggesting that adversity may accelerate typical developmental trends that occur during this age range.

To understand how these brain changes might affect behavior, the researchers examined whether the altered connections were linked to changes in mental health symptoms or school grades. Interestingly, the brain changes associated with adversity were linked to fewer internalizing symptoms, such as sadness or anxiety, according to parent reports. This suggests that the observed decreases in connectivity may reflect adaptive neural responses that help children regulate emotions in the face of stress.

However, these same brain changes were also linked to lower academic performance. Children with greater decreases in cortical-subcortical connectivity tended to report worse grades at the two-year follow-up, even after accounting for the number of adverse events experienced. There was also some evidence that these changes were associated with increases in externalizing behaviors, such as acting out or disobeying at school, though these findings were weaker.

The study found no evidence that these brain-behavior relationships differed significantly between boys and girls. When the researchers trained their prediction model on data from girls and tested it on boys, and vice versa, the results were largely consistent. This suggests that the brain’s response to adversity may follow similar patterns across sexes during this developmental window.

These findings provide evidence that the brain can adapt to stressful experiences in ways that may buffer emotional distress. The decreases in functional connectivity between cortical networks and subcortical regions, particularly those involved in emotion regulation and alertness, may reflect a kind of accelerated maturation. This aligns with earlier research suggesting that adversity can speed up the development of brain systems responsible for managing threat and stress. However, while this adaptation may reduce vulnerability to anxiety and depression, it may come at a cost to other domains, such as cognitive performance in academic settings.

There are some limitations to keep in mind. Although the researchers used a large and diverse sample and employed rigorous statistical techniques, the findings are still based on observational data. The analysis focused only on discrete adverse events reported during a specific two-year period, which may not capture the full range of chronic or early-life stressors. Additionally, behavioral outcomes were assessed using parent and child self-reports, which may be influenced by subjective perceptions or reporting biases. The correlations between brain changes and behavior were modest in size, and the long-term consequences of these changes remain unclear.

Future research will be needed to determine whether the observed brain alterations persist into adolescence or adulthood and whether they predict longer-term outcomes such as mental illness or educational attainment. It will also be important to examine whether different types of adversity, such as deprivation versus threat, have distinct effects on brain development. Further exploration of protective and compensatory brain responses may inform interventions aimed at promoting resilience in children facing stress and adversity.

The study, “The effects of adverse life events on brain development in the ABCD study®: a propensity-weighted analysis,” was authored by Amanda Elton, Ben Lewis, and Sara Jo Nixon.