Researchers know that adversity-especially poverty-related adversity-increases the risk for anxiety and depression.
Now, University of Michigan researchers have won a $6.7 million grant to study how poverty-related adversity might affect the development of threat and reward systems in the brain, and how that developmental process might increase the risk for people to develop anxiety and depression.
Specifically, the grant will allow researchers to work with people often overlooked in these kinds of studies: low-income and African American participants. The study will also help researchers explore sources of resilience for people facing adversity.
"We know that violence exposure in the neighborhood, parental neglect and poverty are variables that affect risk for mental illness, but we don’t really know how these adverse experiences get under the skin, and tweak biology and other aspects of brain function to increase risk for anxiety and depression,” said co-principal investigator Christopher Monk, professor of psychology and of psychiatry and research professor in the Survey Research Center at the Institute for Social Research.
"The brain is very plastic and constantly changing, so by understanding how adversity affects the brain, we can also find ways to support those facing adversity and understand why some people are resilience in these contexts.”
The grant will also allow the researchers to tease out characteristics of depression and anxiety in order to help them better understand these kinds of disorders. Currently, the boundaries of depression and anxiety are poorly understood and could be part of the same disorder, or made up of many different disorders altogether, says co-principal investigator Luke Hyde, associate professor of psychology and SRC faculty associate.
"A good analogy is cancer. Cancer can be in many parts of the body and look different in different places, but it’s mostly defined by the underlying pathology of abnormal cell growth,” Hyde said.
"What we commonly think might be depression might actually be multiple different disorders, or disorders we think are separate disorders such as depression and anxiety might be the same underlying disorder. We might be measuring a ’fever’ that is potentially a symptom of multiple different underlying disorders and not the disorder itself.”
The grant will contribute to what’s called the RDoC Initiative, or the Research Domain Criteria Initiative. Developed by the National Institute of Mental Health, the initiative aims to use neuroscience and behavioral science to better understand the structure of mental disorders and their underlying pathology.
The study will recruit participants from the Fragile Families and Child Wellbeing Study, a long-running study based at Princeton and Columbia universities that has followed the same group of 5,000 children since birth. The Fragile Families study interviews mothers, fathers and/or primary caregivers of the participating children at birth, and ages 1, 3, 5, 9 and 15, collecting information on relationships, parenting behavior, demographic characteristics, mental and physical health, economic and employment status, and neighborhood characteristics.
"Most neuroimaging studies have studied mostly white, middle-class college undergraduates,” Hyde said. "Part of what we’re doing is looking at what happens to children and families who are exposed to high levels of adversity, such as those living in poverty and underrepresented minorities who are disproportionately exposed to stressors to try to understand how and why adversity is so toxic to the brain.
"We also want to learn about sources of strength in families who manager to thrive in difficult situations and use our work to inform interventions and policies to strengthen families and communities.”
Previously, the U-M researchers were able to gather more information from families in Detroit and Toledo when the children were 15 and 17. This included a full mental health diagnostic interview, levels of the stress hormone cortisol and an MRI scan of a participant’s brain.
Now, the U-M researchers’ grant will allow them to bring the participants back for two more visits, at ages 21 and 24, as they’re transitioning from adolescence to young adulthood. The researchers will also expand the sample size from 237 participants to a total of 606 participants by including young adults from other cities in the Fragile Families study.
During the two follow-up visits, the participants will be scanned using MRI, charting how the structure and function of the brain is changing across early adulthood and how that might signal risk for mental disorders. The study will also use machine learning algorithms and other big data techniques to better understand how all of the pieces fit together.
Better understanding how depression and anxiety develop, may ultimately help researchers predict who is at risk for developing them to potentially get a jumpstart on treatment.
"The ultimate goal is to find a mechanism: here is a poverty-related stressor, here’s how it changes the brain, and here’s how the changing of the brain led to this person having depression,” said Colter Mitchell, co-principal investigator and research assistant professor in ISR’s SRC and faculty associate of the Population Studies Center.
"Potentially learning the mechanism by which these disorders are operating-if it’s exposure to toxicants or diet or poverty or some combination of these-can help us tailor our interventions more precisely and inform policies that might protect youth from toxic environments.”
The grant is funded under 1R01MH121079.