Teens who faced high levels of emotional and multidimensional adversity in their early years are at the most significant risk for mental health challenges, a comprehensive 15-year study has revealed.

These teens also exhibit significant differences in brain activity related to emotion processing, according to University of Michigan research published in JAMA Network Open.

The study tracked over 4,000 youths from birth to age 15, examining how a range of childhood adversities—such as maltreatment, family violence and maternal depression—affect later mental health and brain function.

The findings showed that youth exposed to high levels of adversity in multiple contexts (home, family, neighbourhood) suffered worse mental health outcomes and altered brain function. Notably, maternal depression alone could produce similar negative effects, even when other adversities were only moderate.

Using a clustering method, researchers identified four profiles of childhood adversity:

1. Low adversity: Minimal exposure to adverse experiences
2. Medium adversity: Moderate levels across various domains
3. Maternal depression: Moderate adversity with high levels of maternal depression
4. High adversity: Significant adversity across all measured domains

"Adverse childhood experiences occurring within and outside the home are considered pervasive risk factors for poor health," said Christopher Monk, professor of psychology and psychiatry and research professor at the U-M Institute of Social Research.

"However, there are important variations in the adverse environments that children are exposed to. While many studies have examined the impact of adverse experiences, little is known about how these different combinations of adversities can shape individuals' mental health and brain function."

Using a combination of two statistical techniques—the Latent Profile Analysis and Group Iterative Multiple Model Estimation—researchers were able to pinpoint how different adversities, such as maternal depression, lead to specific mental health outcomes and changes in brain function during adolescence.

"The impact of adverse childhood experiences unfortunately can span years of development," said U-M alum Felicia Hardi, now a postdoctoral fellow at Yale University. "Individuals at the greatest risk of harm are those who are growing up in environments with many different risk factors and those with parents who have poor mental health."

According to Monk, Hardi and colleagues, even in the absence of high levels of other types of adversities, youth growing up with mothers with depression showed similar mental health symptoms and emotion-related brain connectivity patterns to those youth exposed to the highest risk factors. This underscores the critical contribution of maternal mental health to children's emotional development.

"Effective policies and interventions should address multiple risks and emphasize support for mothers to promote the long-term mental health of youth," Hardi said.

Researchers are continuing to follow these youths into young adulthood, allowing future studies to explore the long-term effects of early adversity on health outcomes throughout life.