Poverty is bad for your brain.
That's the basic takeaway from an emerging body of research suggesting that the distress associated with growing up poor can negatively influence brain development in many ways, and in certain cases might also lead to emotional and mental health problems, like depression.
The latest study, led by researchers at Washington University School of Medicine in St. Louis, found that poverty in early childhood may influence the development of important connections between parts of the brain that are critical for effective regulation of emotions.
The study, published in the Journal of American Psychiatry, adds "to the growing awareness of the immense public health crisis represented by the huge number of children growing up in poverty and the likely long-lasting impact this experience has on brain development and on negative mood and depression," researchers report.
Specifically, the researchers conclude: "...Poverty in early childhood, as assessed by at least one measure, may influence the development of hippocampal and amygdala connectivity in a manner leading to negative mood symptoms during later childhood."
The study involved 105 St. Louis-area children participating in a larger study looking at the development of emotions. Starting in pre-school, the children underwent behavior assessments for up to 12 years, researchers report, then at school-age they underwent brain scans with functional MRI.
I asked Harvard professor, Dr. Charles Nelson, a Boston Children’s Hospital neuroscientist not involved in the St. Louis study, for his thoughts. Nelson, who studies how children’s early experiences shape their developing brains, wrote back in an email, which is lightly edited, here:
This paper represents an emerging literature that links exposure to early adversity writ large with alterations in brain and behavioral development; in this case, it specifically focuses on the effects of poverty on neural connectivity.
The sample reported on here is part of an ambitious longitudinal study that has been yielding very exciting findings. For example, in an earlier paper by [Joan] Luby et al., published in JAMA Pediatrics, the authors reported that children growing up in low [socio-economic status] households showed changes in the volume [size] of the hippocampus and amygdala, structures that play an essential role in learning, memory, and emotion.
The Luby finding is consistent with other work by Kim Noble and colleagues, that collectively suggest that growing up poor alters the course of key brain structures; however, in the Luby paper the authors went one further and demonstrated that the effects on brain structure were mediated by parental sensitivity — thus, it isn’t simply being poor that accounted for the findings, it was parental responsiveness.
The current paper extends the earlier findings by Luby by suggesting that it is not only the volume [size] of the hippocampus and amygdala that is compromised by growing up poor, it is the connections between these structures. Importantly, then they report that altered connectivity is associated with (i.e., can account for) depressive symptoms in this sample.
The work is well done and moves the ball further downfield (since we’re in the midst of Patriot fever I thought I’d use a football analogy), informing us that of the potential hazards of growing up poor.
Now, is there a down side here? Yes. We still need to “peak inside” of poverty; poverty per se doesn’t cause anything, it is the host of things that travel with poverty. Is it access to resources? Stress? Less than adequate care-giving? We really don’t know. But, the work is very important in pointing to the neurobiological toll of growing up poor.
As I note in my commentary on the Luby paper, the costs of the effects reported in this paper and in this group’s other papers extends far behind childhood; these effects can be biologically embedded and lead to less than desirable outcomes in the adults these children become.