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A recent study published in the Proceedings of the National Academy of Sciences of the United States of America examined whether extreme adversity early in life can have a long-lasting impact on brain development. Previous research shows that early childhood adversity is linked to a higher risk for a wide range of neurodevelopmental and psychiatric problems later in life. This study examined whether early adversity is also linked to changes in brain structure and whether these brain changes can partly explain why some individuals develop persisting neurodevelopmental problems, such as attention-deficit/hyperactivity disorder (ADHD), following adversity while others do not.

“The human brain goes through dramatic developmental changes in the first years of life,” study author Nuria Mackes told us. “It is particularly susceptible to environmental influence during this time. On the one hand, this allows infants to learn and achieve the developmental milestones associated with these early years. On the other hand, it may leave the brain particularly vulnerable to the negative effects of adverse experiences such as maltreatment. Based on this, we predicted that extreme adversity experienced in institutions early in life would be associated with long-lasting changes in brain structure which cannot be completely overcome by later environmental enrichment when the brain is less malleable.”

UNICEF estimates that more than five million children worldwide live in institutional care. Countless more live in extreme poverty or experience other forms of adversity. While early adversity is a risk factor for mental illness and neurodevelopmental problems later in life, there are also many individuals who do not develop such problems. Using brain imaging to better understand this variability might not only address the fundamental question of how early experiences shape brain development but it might also help researchers to develop preventive and therapeutic approaches to help those who are negatively impacted by childhood adversity.

“The English and Romanian Adoptees Study follows the development of a group of Romanian adoptees, who were exposed to severe deprivation in institutions during the Ceaușescu regime before being adopted into nurturing families in the U.K.,” Mackes told us. “The Romanian adoptees experienced a stark contrast of extreme adversity very early in life followed by enrichment and a loving environment in later childhood and adolescence. As a comparison group this study examined a group of U.K. adoptees, who were not exposed to any institutional deprivation. By comparing Romanian and U.K. adoptees, we tested whether institutional deprivation was associated with changes in brain structure in young adulthood.”

Researchers found that institutional deprivation was associated with smaller total brain volume in young adulthood. Moreover, there was a direct relationship with the duration of deprivation where the longer the adoptees had spent in the institutions, the smaller their brains tended to be. Deprivation-related smaller total brain volume was also linked to lower IQ and higher ADHD symptoms.

“Beyond the global effect described above, we found that some brain regions in the frontal and temporal parts of the brain seemed to be particularly sensitive to deprivation,” Mackes told us. “Surprisingly, changes in a brain region in the temporal part of the brain, the inferior temporal cortex, were associated with lower symptoms of ADHD. This suggests that this change in brain structure might actually be compensatory in nature, rather than impairing, as it was associated with better outcomes.

Researchers say this study has shown that early institutional deprivation is associated with long-term changes in brain structure that are still visible in adulthood – more than 20 years after the adoptees left the institutions. These findings provide compelling evidence for the notion that extreme adversity early in life can lead to fundamental changes in brain development which cannot be completely overcome by later environmental enrichment.

“This research stresses the importance of early experiences on brain development,” Mackes told us. “By linking brain structure and neurodevelopmental outcomes, we were also able to show that we can use brain imaging to gain a better understanding of why some individuals develop problems following adversity while others do not. Future research is needed to identify how we can best prevent and treat psychiatric conditions that can arise following severe adversity. For example, it would be interesting to see whether the compensatory processes in the inferior temporal cortex found in this study could be targeted in cognitive training to reduce ADHD symptoms in individuals who experienced early deprivation.”