Childhood Adversity Linked to Premature Brain Development and Mental Illness
New research shows that growing up in poverty and experiencing traumatic events such as a bad accident or sexual assault can negatively impact brain development and behavior in children and young adults.
According to a new study, low socioeconomic status (L-SES) and experiencing traumatic stressful events (TSEs) were linked to accelerated puberty and brain maturation, abnormal brain development, and greater mental health disorders, such as depression, anxiety, and psychosis.
“The findings underscore the need to pay attention to the environment in which the child grows. Poverty and trauma have strong associations with behavior and brain development, and the effects are much more pervasive than previously believed,” said the study’s lead author, Raquel E. Gur, MD, PhD, a professor of Psychiatry, Neurology, and Radiology at the Perelman School of Medicine at the University of Pennsylvania, and director of the Lifespan Brain Institute.
The researchers acknowledge that parents and educators are split into opposing camps regarding the question of how childhood adversity affects development into mature, healthy adulthood.
Views differ from “spare the rod and spoil the child” to concerns that any stressful condition, such as bullying, will have harmful and lasting effects.
Psychologists and social scientists have documented lasting effects of growing up in poverty on cognitive functioning, and clinicians observed effects of childhood trauma on several disorders, though mostly in the context of post-traumatic stress disorders (PTSD).
There are also anecdotal observations, supported by some research, that adversity accelerates maturation, the researchers noted. Children become young adults faster, physically and mentally.
Neuroscientists, who are aware of the complexity of changes that the brain must undergo as it transitions from childhood to young adulthood, suspected that childhood adversity affects important measures of brain structure and function.
The new study was the first to compare the effects of poverty (L-SES) to those who experienced TSEs in the same sample set, according to the Penn researchers.
The researchers analyzed data from the Philadelphia Neurodevelopmental Cohort, which included 9,498 participants between the ages of 8 and 21. The racially and economically diverse cohort includes data on SES, TSEs, neurocognitive performance, and in a subsample, multimodal neuroimaging taken via MRI.
The researchers found specific associations of SES and TSE with psychiatric symptoms, cognitive performance, and several brain structure abnormalities.
The findings revealed that poverty was associated with small elevation in severity of psychiatric symptoms, including mood and anxiety, phobias, externalizing behavior, such as conduct disorder and ADHD, and psychosis, as compared to individuals who did not experience poverty.
The magnitude of the effects of TSEs on psychiatric symptom severity was unexpectedly large, the researchers discovered.
TSEs were mostly associated with PTSD, but the researchers also found that even a single TSE was associated with a moderate increase in severity for all psychiatric symptoms analyzed. Two or more TSEs showed large increases, especially in mood and anxiety and in psychosis.
Additionally, the study’s findings showed that these effects were larger in females than in males.
With neurocognitive functioning, the case was reversed: Poverty was found to be associated with moderate to large cognitive deficits, especially in executive functioning — mental flexibility, attention, and working memory — and in complex reasoning, the researchers report.
TSEs were found to have very subtle effects, with individuals who experienced two or more TSEs showing a mild deficit in complex cognition, but demonstrating slightly better memory performance, according to the study’s findings.
Both poverty and TSEs were associated with abnormalities across measures of brain anatomy, physiology, and connectivity, the researchers discovered.
Poverty associations were widespread, while TSEs were associated with more focused differences in the limbic and fronto-parietal regions of the brain, which processes emotions, memory, executive functions and complex reasoning.
The researchers also found evidence that adversity is associated with earlier onset of puberty.
Both poverty and experiencing TSEs are associated with the child physically maturing at an earlier age. The researchers also found the same effects on the brain, with findings revealing that a higher proportion of children who experienced adversity had characteristics of adult brains. This affects development, as the careful layering of the structural and functional connectivity in the brain requires time, and early maturity could prevent the necessary honing of skills, the researchers explained.
“Altogether our study shows no evidence to support the ‘spare the rod’ approach, to the contrary we have seen unexpectedly strong effects of TSEs on psychiatric symptoms and of poverty on neurocognitive functioning, and both are associated with brain abnormalities,” Gur said.
“The study suggests that it makes sense for parents and anyone involved in raising a child to try and shield or protect the child from exposure to adversity. And for those dealing with children who were already exposed to adversity — as is sadly the case today with refugees around the world — expect an increase in symptoms and consider cognitive remediation, a type of rehabilitation treatment which aims to improve attention, memory, and other cognitive functions.”
The study was published in JAMA Psychiatry.