The American Journal of Psychiatry reported Friday (Jan. 15) that researchers at Washington University, St. Louis analyzing 105 brain scans from children ranging in ages from 7 to 12, found that within the brains of children living in poverty, there were altered connections of the hippocampus and amygdala structures to the brain.
The hippocampus is a structure critical to learning, memory, and stress regulation. The amygdala is linked to stress and emotional control. The weakened brain connections of these structures may be a cerebral marker for later onset of clinical depression.
Working from a National Institute of Mental Health of the National Institutes of Health (NIH) grant, researchers measured poverty via an income-to-needs ratio, taking into account the child’s family’s size and annual household income. The degree of child poverty apparently mutates the hippocampus and amygdala connections to the brain.
The identifiable weakened connectivity is detectable via functional MRI scans showing areas within the brains of children living in poverty. Normal connectivity is highlighted in red and blue. However, weakened connectivity is highlighted in green. “The areas in green are among several areas — detailed in other brain scans — where connections are weakened in children raised in poverty.”
According to the study, preschoolers identified as living in higher levels of poverty, were also more likely to have weaker brain connections of the hippocampus and amygdala, followed by symptoms of clinical depression. Depression diagnosis were routinely given when the studied children reached school age. Child participants of the study who were poor as preschoolers, were more likely to be clinically depressed by age 9 or 10.
Prior research from investigators in this study revealed significant differences in gray matter volume and white matter, and the size and volume of the hippocampus and amygdala. These differences were reportedly surmountable by intervention of nurturing from parents. However the same intervention did not have the same positive effect on weakened brain connections marked in the current study.
Co-investigator, Joan L. Luby, MD (the Samuel and Mae S. Ludwig Professor of Child Psychiatry and director of Washington University’s Early Emotional Development Program) said that, “Poverty is one of the most powerful predictors of poor developmental outcomes for children… Previously, we’ve seen that there may be ways to overcome some brain changes linked to poverty, but we didn’t see anything that reversed the negative changes in [brain structure] connectivity…”
In the United States, major depressive disorder is the preeminent cause of disability for people ages 15-44 in any given year, affecting approximately 14.8 million American adults (or about 6.7 percent of the U.S. population age 18 and older). The median age at onset of illness is 32 years according to the National Institute of Mental Health.
Further, nearly half (45 percent) of the mentally challenged population within the U.S., meets or exceeds criterion of two or more co-occurring mental disorders. Comorbidity is strongly related to the severity of a person’s ill conditions (NIMH).
The brain connectivity research comes on the heels of the recent groundbreaking discovery of a genetic marker for autism that may allow early diagnosis and management of autism.