New research provides evidence that the generosity of a state’s anti-poverty policies and the cost of living play a pivotal role in shaping the long-term outcomes for children raised in low-income families. The findings shed light on how structural factors can mitigate or exacerbate the impact of low income on brain development and mental health, offering hope for targeted policy interventions to level the playing field for disadvantaged children.
The study was published in Nature Communications.
The researchers conducted this study to understand why adults who grew up in families with lower income tend to have lower educational attainment, more mental and physical health problems, and rely more on public assistance compared to those from higher income families. They wanted to explore whether certain factors, like the cost of living and the generosity of anti-poverty policies, influence the relationship between family income and brain development and mental health in children.
“Kids growing up in lower income households tend to have more mental health problems, like depression and anxiety then kids from higher income households,” said study author David G. Weissman, a postdoctoral fellow at Harvard University and an incoming assistant professor at California State University Dominguez Hills.
“Many studies have also found poverty or lower family socioeconomic status to be associated with structural differences in the developing brain. The solutions that have the potential for the most widespread impact on these disparities are at the level of state and federal policy, but most neuroscience studies are conducted at a single place and time, where it is not possible to study the impacts of these types of policies.
To conduct the study, the researchers used data from a large study called the Adolescent Brain and Cognitive Development (ABCD) Study, which involved children from different states in the United States. They looked at family income, brain structure (specifically the size of the hippocampus), and mental health symptoms of children aged 9 to 11.
“The hippocampus is central to memory and learning, and it’s also uniquely sensitive to chronic stress. Animal studies show that consistently elevated stress hormones such as cortisol can reduce the formation of new synapses (or connections between neurons) in this region of the brain,” Weissman told PsyPost.
The study included a total of 11,864 youth with data on parent-reported psychopathology and 11,533 youth with brain structure data. The average monthly Earned Income Tax Credit (EITC) and Temporary Assistance for Needy Families (TANF) benefits in each state were used to measure the generosity of anti-poverty policies. Additionally, the researchers used a dichotomous variable to indicate whether each state had expanded Medicaid eligibility through the Affordable Care Act by the end of 2017.
“Because the ABCD study collected data from 21 sites in 17 states across the country, we had a unique opportunity that has not been possible with previous studies on this topic,” Weissman explained. “We were able to look at if characteristics of those places, in particular government antipoverty programs, influenced the nature of the associations between poverty and both brain structure and mental health.”
The researchers found that lower family income was associated with smaller hippocampal volume and more mental health symptoms in children. Additionally, they discovered that in states with a higher cost of living, the differences in brain structure and mental health between children from high- and low-income families were greater.
However, in states with more generous anti-poverty programs, these differences were reduced, meaning that children from low-income families had better brain development and mental health outcomes when they lived in states with more supportive policies.
“Many studies have shown that the impacts of poverty are observable in children’s brains,” Weissman told PsyPost. “These results suggest that government antipoverty programs work at reducing those impacts. Therefore, policy decisions on things like Medicaid Expansion and the generosity of cash assistance for families in poverty matter for the brain development and mental health of children from those families in a measurable and significant way.”
The researchers suggest that factors like cost of living and anti-poverty policies can either amplify or reduce the impact of low income on brain development and mental health. For example, living in a high-cost-of-living state can put more strain on low-income families, but having access to generous anti-poverty programs can provide more financial resources and support, potentially reducing stress and its negative effects on brain development and mental health.
“While the results were more or less what we expected, it is nonetheless striking how consistent the pattern of results were for both the effects of both cash assistant programs and Medicaid expansion on both hippocampal volume and internalizing problems,” Weissman said.
The researchers controlled for other state-level social, economic, political, and educational factors that might influence the relationship between family income, brain structure, and mental health. These included population density, unemployment rate, political preferences, and state-funded preschool enrollment. But like all research, the study includes some caveats.
“These findings are correlational, and there are other differences between these states that could explain these findings,” Weissman explained. “Experimental evidence, such as from randomized control trials of cash transfer programs like the Baby’s First Years Study at Columbia, can more firmly establish that these types of programs cause differences in brain structure and mental health.”
“But we tried to rule as many alternative explanations out as we could by conducting supplemental analyses controlling for a wide array of state characteristics, from the racial and ethnic makeup of the sample within that state to its population density to measures of education equity in those states, and the results held consistently across these analyses.”
The study, “State-level macro-economic factors moderate the association of low income with brain structure and mental health in U.S. children“, was authored by David G. Weissman, Mark L. Hatzenbuehler, Mina Cikara, Deanna M. Barch, and Katie A. McLaughlin.
