Abstract: This study investigates the long-term neuropsychiatric impacts of combat-associated traumatic brain injuries (TBI) in British veterans, using data from the ADVANCE-TBI cohort, which followed 1,145 active duty and retired military personnel for up to 8 years post-injury. It highlights the high prevalence of mild TBIs, often overlooked by the medical system, and their association with neurocognitive disorders, psychological distress, and quality-of-life deterioration. The study explores blood biomarkers such as glial fibrillar acidic protein (GFAP) and neurofilament light (NfL), which may reflect TBI severity and serve as potential diagnostic tools for monitoring chronic TBI effects. Findings suggest that TBI-induced biochemical changes persist for years, underscoring the need for ongoing research and intervention strategies to address the long-term consequences of neurotrauma in veterans.