New research published in Biological Psychiatry reveals that different types of early-life adversity can lead to distinct patterns of brain development. The study found that children who experience emotional neglect tend to have younger-looking brains. On the other hand, children exposed to more other forms of adversity, such as caregiver mental illness and socioeconomic hardship, often have older-looking brains. These findings provide new insights into how varied early-life experiences can shape the developing brain in different ways.
While previous studies have shown that exposure to adversity can alter brain structure and function, most of this research has focused on singular types of adversity, like violence or poverty, or has combined multiple forms of adversity into a single measure. This approach, however, might miss the nuances of how different types of adversity affect the brain differently. The authors behind the new study wanted to address these limitations by investigating how distinct dimensions of early-life adversity affect brain development.
“I was mainly interested in this topic due to the growing body of research that suggests that different types of adversity (such as those related to emotional or physical neglect or threatening environments where a child experiences physical or sexual abuse) can have differential effects on the developing brain,” said study author Dani Beck, a postdoctoral researcher of neurodevelopment at the University of Oslo and Diakonhjemmet Hospital in Oslo.
“I wanted to test this using brain age prediction, a machine learning algorithm that provides an estimation of an individual’s ‘biological’ age based on characterises of their magnetic resonance imaging (MRI) scan. Here, the predicted age can be compared to their chronological age (termed the brain age gap or BAG) and this information can be used to see if an individual’s brain is older or younger-looking in the context of a phenotype, for example, in this case, early life adversity.”
For their study, the research team used data from the Adolescent Brain Cognitive Development (ABCD) Study, which includes a large sample of children and adolescents from across the United States. The ABCD Study is an ongoing project that tracks the brain development and health of children over time, making it a valuable resource for studying the effects of early-life adversity.
The researchers focused on a sample of approximately 11,800 children aged 9 to 14 years old. The key measure they focused on was the brain age gap. A positive brain age gap indicates that the brain appears older than expected for the child’s age, while a negative brain age gap suggests a younger-looking brain.
In addition to brain imaging, the researchers analyzed detailed information on the children’s early-life experiences. Previous work had identified ten different dimensions of adversity, such as emotional neglect, caregiver mental illness, socioeconomic disadvantage, trauma exposure, and family conflict. These dimensions were determined through a combination of child and parent reports, as well as assessments by researchers.
The researchers found that children who experienced emotional neglect—such as a lack of support from their primary and secondary caregivers and insufficient supervision—tended to have younger-looking brains. This finding suggests that emotional neglect may delay brain maturation, possibly because the absence of emotional and social support slows the development of certain brain structures.
On the other hand, children who were exposed to more severe forms of adversity—such as caregiver mental illness, socioeconomic disadvantage, family aggression, trauma, and separation from a biological parent—were more likely to have older-looking brains. This suggests that these more intense forms of adversity might accelerate brain development, potentially as an adaptive response to stressful or dangerous environments. For instance, children living in unsafe neighborhoods or with caregivers who have mental health issues might develop faster to cope with these challenging circumstances.
“Although there are theories such as Threat versus Deprivation and The Stress Acceleration Hypothesis that suggest violent and threatening environments are conceptually different and have different impacts on the developing brain than emotional neglect and deprivation, I was still surprised that the dimensions we explored (which are derived from a data-driven approach) loaded so intuitively with accelerated and delayed maturational patterns that seem to support previous work,” Beck told PsyPOst
Interestingly, the study also found that the impact of certain adversities, like caregiver mental illness and family aggression, became more pronounced over time. This means that as children grew older, the brain age gap for those who had experienced these types of adversity increased, indicating a greater divergence from typical brain development patterns. This finding suggests that the effects of these adversities on brain development may accumulate or intensify as children grow older.
“The main take away from the research is that our results suggest that dimensions of early-life adversity are differentially associated with distinct neuro-developmental patterns, indicative of dimension-specific delayed and accelerated brain maturation,” Beck said. “Our findings are generally in line with theories positing that adverse experiences related to threat versus deprivation are two different dimensions, though further research is needed.”
While the study provides insights into how different types of early-life adversity affect brain development, it also has limitations to consider. The study’s findings are based on data from the ABCD Study, which includes a large but relatively general sample of children. This means that the results may not fully capture the effects of more extreme forms of adversity, such as severe abuse or chronic neglect, which might be underrepresented in the sample.
“The sample we used is not enriched for adversity exposure,” Beck explained. “And while this is good for facilitating broader generalization, more research is needed on children exposed to more severe forms of adversity. There remain also additional challenges such as accounting for differences in chronicity of adversity events, interindividual differences in resilience, and overlap in adversity types.”
The study, “Dimensions of Early Life Adversity Are Differentially Associated with Patterns of Delayed and Accelerated Brain Maturation,” was authored by Dani Beck, Lucy Whitmore, Niamh MacSweeney, Alexis Brieant, Valerie Karl, Ann-Marie G. de Lange, Lars T. Westlye, Kathryn L. Mills, and Christian K. Tamnes.
