Summary: Difficult social environments and left hippocampal size contribute to increased risk of depression in children ages 9-11. Researchers found that children with larger hippocampal volume were more sensitive to negative social environments and had worse depressive symptoms over a two-year period.
“This study highlights the interplay between brain structure and social context and suggests that some children may be more vulnerable to social stressors than others. The findings underscore the need for an individualized approach to adolescent mental health support.”
Key Facts:
Larger left hippocampal volumes make children more sensitive to negative social environments. Difficult social situations are linked to worsening depressive symptoms in young people. Because brain sensitivity varies from person to person, individualized mental health support is essential.
Source: Northwestern University
As the mental health crisis impacts the lives of young people across a wide range of age groups, a new Northwestern University study finds that the presence of difficult social environments and the absence of positive social environments predict significant increases in depressive symptoms among 9- to 11-year-olds over a two-year period.
In addition to the environment, left hippocampal volume amplifies the effects of social context, suggesting that youth with a larger left hippocampus experience greater increases in major depressive disorder symptoms in challenging social spaces.
“We hope that our study will not only influence future research, but also raise awareness among parents, educators, mental health professionals and policymakers,” said co-lead author Claudia Haas, associate professor of human development and social policy in Northwestern University’s School of Education and Social Policy (SESP).
“Over the years, opinions have shifted, with some researchers and practitioners emphasizing the role of nature and others emphasizing the role of nurture, and we’ve really come to understand that we need to look at both and their interplay together.”
The study, published in the Proceedings of the National Academy of Sciences, highlights the importance of family, peers and school in the development of adolescent depression and how variations in neural structure may amplify or reduce sensitivity to the environment.
The study was first authored by SESP doctoral student Mathias Martinez, along with senior co-authors Haase and Yan Qu, associate professor of human development and social policy at SESP. Titled “Depressive Symptoms in the Transition to Adolescence: Left Hippocampal Volume as an Index of Social Context Sensitivity,” other authors on the study include Tianying Cai, Beiming Yang, Zexi Zhou, Stewart Shankman, and Vijay A. Mittal.
“Our study highlights the importance of paying attention to individual differences and that some people are more sensitive to their social environment than others,” Qu said. “We should never assume that the same environment has the same effect on everyone. There is no one-size-fits-all solution.”
Survey results
Because neuroscience has made great advances in recent years, the researchers focused on brain-based susceptibility to the development of depressive symptoms.
“Previous studies have focused on physiological processes or genetic variants, but with developments in neuroscience, we can now examine what role the brain may play in sensitivity to the environment,” Martinez said.
“While there has been long-standing debate about whether some individuals are more or less sensitive to the environment, in this study we focused on sensitivity to both good and bad experiences.”
The results led to the conclusion that the left hippocampus, an area of the brain primarily associated with memory, learning, and how we experience the world around us, plays a key role in whether a person becomes depressed when in a difficult social space. The larger the hippocampus, the better a person’s ability to recall experiences and recall memories.
“This is one of the most plastic parts of the brain,” Martinez said, “and it’s very sensitive to the environment, especially during early childhood. Our findings suggest that this brain region may make young people more sensitive to challenging circumstances and lack of positivity in their life experiences, which may play a role in causing symptoms of depression.”
If this part of a child’s brain is larger, that child may be more sensitive into adolescence to social experiences such as family conflict, depression in their primary caregiver, peer victimization, parental warmth, and a prosocial school environment.
“When it comes to the human brain, we tend to think of it as something we’re born with, but the more we learn about the brain, the more scientists realize how open and flexible our brains are, not just in early childhood but throughout our lives,” Haas said.
“Our brains change in response to the environment we’re in, and research shows that this is certainly true for the hippocampus as a brain region.”
method
The researchers looked at two-year longitudinal data from the Adolescent Brain Cognitive Development Study, one of the largest in the U.S., conducted at 21 research sites across the country and tracking a diverse sample of 11,800 9- to 11-year-olds for 10 years, to monitor cognitive, brain, social, and emotional development over time.
“The ABCD Study is extraordinary, and I’m incredibly grateful to the National Institutes of Health and all the researchers involved who made it possible, and of course to all the young people and their families who are participating,” Qu said. “This is the largest longitudinal study of brain development and child health in the United States.”
Data revealed that the association between social experience environment and MDD symptoms was stronger in youth with larger left hippocampal volume, and that among individuals with different left hippocampal sizes, MDD symptoms did not differ between low and high levels of exposure to negative situations.
What’s next?
The researchers hope that this study can help parents, teachers, and policymakers better understand and support the mental health of adolescents, and Martinez hopes that by expanding the study, they will be able to better explain how children in difficult social environments adapt in the long term.
“The ABCD study is a comprehensive project that will continue to follow young people’s development for years to come,” Martinez said. “It will be interesting to see how different environmental exposures, hippocampal volume, and depressive symptoms interact as young people move through their teenage years.”
About this news article on depression and neurodevelopment research
Author: Shanice Harris
Source: Northwestern University
Contact: Shanice Harris – Northwestern University
Image: This image is provided by Neuroscience News
Original research: The findings will be published in PNAS
