Research Spotlight: Environmental Influences Account for More Differences in Child Emotional and Behavioral Symptoms Than Genetic Factors

Researchers in the Center for Precision Psychiatry at Massachusetts General Hospital have published a new study, Integrative Analysis of Genomic and Exposomic Influences on Youth Mental Health, in the Journal of Child Psychology and Psychiatry. The study was conducted by Karmel Choi, PhD, clinical psychologist in the Department of Psychiatry at Massachusetts General Hospital and assistant professor at Harvard Medical School, Jordan Smoller, MD ScD, professor of psychiatry at Harvard Medical School, and colleagues from the Massachusetts General Hospital, Harvard Medical School, University of South Australia, and University College of London. 

What was the question you set out to answer with this study?

How do genes and environments work together to shape emotional and behavioral problems in young people?

In a longitudinal cohort of over 4,000 children across the United States with rich genomic, environmental, and clinical data, we captured an “exposome” of 133 different environmental variables across multiple levels (peer, family, school, neighborhood, life events), and applied a novel statistical approach to break down how much differences in child emotional and behavioral symptoms could be explained by the exposome, genome, as well as interplay between the two.

What are two or three key takeaways?

1. Environmental influences overshadowed genetic contributions to mental health in children—compared to the genome, the exposome accounted for twice as much variation (16-23% versus 6-7%) in child emotional and behavioral symptoms.
2. Wide-ranging environmental factors (especially peer, family, school, and stressful life experiences) also interacted with genome-wide variation to explain an additional 13-33% of differences in child emotional and behavioral problems.
3. By combining genomic and exposomic information, we were able to identify the majority of children who went on to develop significant emotional and behavioral symptoms one year later.
4. Peer, family, and school environments were especially relevant for behavioral symptoms (e.g., aggression, antisocial behavior), whereas stressful life experiences were especially relevant for emotional symptoms (e.g., depression, anxiety).

What were your conclusions?

This study aimed to dissect genetic and environmental influences on child mental health in the most comprehensive way to date.

• Environmental influences account for more differences in child emotional and behavioral symptoms than genetic factors.
• The environment may play at least two key roles in children’s mental health: it affects their mental health directly and through its interplay with genetic factors.
• Models combining genome-wide and environment-wide information as well as their interactions may help to identify children at risk for experiencing emotional or behavioral problems.
• A better understanding of the environment-wide components of children’s mental health risk may inform the design of early prevention strategies.

About the Massachusetts General Hospital

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In July 2022, Mass General was named #8 in the U.S. News & World Report list of "America’s Best Hospitals." MGH is a founding member of the Mass General Brigham healthcare system.