Date of Award

Spring 5-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Psychology

Program/Concentration

Psychology

Committee Director

Sage Hawn

Committee Member

Xiao Yang

Committee Member

Michelle L. Kelley

Abstract

Mild traumatic brain injury (mTBI), often referred to as a “silent epidemic,” accounts for the majority of traumatic brain injuries worldwide and is increasingly linked to persistent psychiatric outcomes. Despite its prevalence, mTBI remains understudied due to diagnostic challenges, underreporting, and misperceptions of its clinical significance. The present study examined whether peripheral biomarkers of neuroinflammation and astroglial injury—tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and glial fibrillary acidic protein (GFAP)— mediate associations between mTBI history and psychiatric symptom severity, including depression, anxiety, and posttraumatic stress disorder (PTSD). Participants were 138 traumaexposed adults recruited from an urban university and surrounding community, with 106 providing viable blood samples for biomarker analysis. The sample was racially diverse (58% White, 42% Non-White), had a mean age of 30.43 years (SD = 11.92), and was predominantly female (71%). Psychiatric symptoms were assessed using validated self-report measures, and plasma biomarkers were assayed using ultra-sensitive Single Molecule Array (Simoa©) technology. Multiple linear regression models and mediation analyses were conducted to examine associations among mTBI history, biomarker levels, and psychiatric outcomes. Results indicated that individuals with a lifetime history of mTBI reported significantly greater PTSD symptoms compared to those without mTBI, even after adjusting for cumulative trauma exposure and covariates. The association between mTBI and depressive symptoms was marginal, and no significant association was observed with anxiety. mTBI was not significantly associated with IL-6 or TNF-α levels and was marginally associated with lower GFAP levels. Biomarkers did not significantly mediate associations between mTBI and psychiatric symptoms. However, IL-6 levels were positively associated with depressive and anxiety symptoms. These findings suggest that while mTBI is associated with increased psychiatric symptom burden, this relationship was not explained by the examined neurobiological markers in this sample. Larger longitudinal studies are needed to clarify the role of peripheral biomarkers in post-injury psychiatric outcomes.

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DOI

10.25777/dzam-7223

ISBN

9798193216711

ORCID

0009-0001-4745-5083

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