Traumatic Stress and Brain Development

A recent study in JAMA Psychiatry by researchers at Children's Hospital of Philadelphia and the University of Pennsylvania highlighted the myriad of associations between low socioeconomic status (L-SES) and traumatic stress events (TSE) on behavior, brain structure, brain function, and puberty, and deepens our understanding of the physical effects of stress on the developing brain.

This paper could be an important reference for preparing grant submissions for programs and research aimed at reducing youth exposure to L-SES and TSE and reducing impact of these exposures.

Researchers analyzed data from the Philadelphia Neurodevelopmental Cohort (comprised of 9,400+ records of children and young adults aged 8 to 21 years from a nonpsychiatric population from 2009 to 2011). Assessment of study participants included in person interviews, self-report of pubertal stage, neurocognitive assessment, and neuroimaging. Brain function was assessed by measuring cerebral blood flow, as well as functional MRI parameters of regional homogenity (ReHo) and amplitude of low-frequency fluctuations (ALFF), parameters typically associated with brain development and performance.

What They Found

Traumatic Stress Events Specific Associations

TSEs were significantly associated with increased behavioral symptom severity across the domains of anxiety/depression, fear, externalizing behavior, and the psychosis spectrum.

• Moderate effect-sized* associations were noted with having one TSE
• Having at least two TSEs had strong associations, particularly among females and mood/anxiety symptoms; and males and psychosis symptoms
• TSEs generally were not associated with differences in neurocognitive performance, except that those with at least two TSEs had better memory and poorer complex cognition.
• TSEs were associated with physical differences:
  • lower volumes in the limbic and frontal regions of the brain, and higher gray matter density (moderate effect size for both associations)
  • mildly reduced CBF
  • lower cortical ReHo in the frontoparietal regions

Low Socioeconomic Status Specific Associations

• L-SES were also significantly associated with increased symptom severity (small effect sizes).
• L-SES and TSEs were associated with a greater proportion of youth completing puberty at an earlier age.
• L-SES was significantly associated with reduced neurocognitive performance across domains, particularly with the complex cognition domain.
• L-SES was also associated with physical differences:
  • lower brain volume across all regions, and lower gray matter density (small effect size for both associations)
  • mildly reduced CBF
  • reduced ReHo and ALFF (particularly in the frontoparietal regions)

L-SES and TSEs were both associated with accelerated brain maturation.

It should be noted that the study analysis found associations but cannot speak to whether L-SES and TSEs caused differences in brain structure and function. The study also did not analyze type of stress exposure or presence/type of treatment. Future studies should look at factors that can prevent reduced neurocognitive effects of these exposures.

*Effect sizes represent the magnitude of a difference, or strength of a relationship.