Early life adversity impacts children’s white matter, leading to cognitive difficulties

Difficult early life experiences, such as exposure to violence, neglect, abuse, poverty, parental mental health issues, and family instability have been linked with diminished white matter connections, a new study has shown. 

White matter are the communication highways that allow the brain networks to carry out the necessary functions for cognition and behaviour. They develop over the course of childhood, and childhood experiences may drive individual differences in how white matter matures.

Published in the journal Proceedings of the National Academy of Sciences (PNAS), the Mass General Brigham study used the experiences of over 9,000 children collected in the Adolescent Brain Cognitive Development (ABCD) study, finding difficult early life experiences were linked with reduced quality and quantity of the white matter communication highways throughout the adolescent brain.

“The aspects of white matter that show a relationship with our early life environment are much more pervasive throughout the brain than we’d thought. Instead of being just one or two tracts that are important for cognition, the whole brain is related to the adversities that someone might experience early in life,” lead author Dr Sofia Carozza said.

The researchers looked at several categories of early environmental factors, including prenatal risk factors, interpersonal adversity, household economic deprivation, neighborhood adversity, and social resiliency factors.

Their analysis revealed widespread differences in white matter connections throughout the brain depending on the children’s early-life environments. In particular, the researchers found lower quality of white matter connections in parts of the brain tied to mental arithmetic and receptive language. These white matter differences accounted for some of the relationship between adverse life experiences in early childhood and lower cognitive performance in adolescence.

“We are all embedded in an environment, and features of that environment such as our relationships, home life, neighborhood, or material circumstances can shape how our brains and bodies grow, which in turn affects what we can do with them,” Dr Carozza said. “We should work to make sure that more people can have those stable, healthy home lives that the brain expects, especially in childhood.”

There was, however, some hope in their work, with the team noting certain social resiliency factors like neighbourhood cohesion and positive parenting may have a protective effect. 

The researchers note that their study is based on observational data, which means they cannot draw strong causal conclusions. Brain imaging was also only available at a single timepoint, offering a snapshot but not allowing researchers to track changes over time. Prospective studies—following children over time and collecting brain imaging information at multiple time points—would be needed to more definitively connect adversity and cognitive performance.

Read the paper here.