The ADVANCE study is a prospective cohort study of British male military personnel deployed on combat operations in Afghanistan between 2003 and 2014. The sample includes serving and former personnel; a group which sustained severe combat-related trauma during the Afghanistan conflict (injured) and a comparison group of the same size matched based on deployment to Afghanistan, age, sex, service, regiment, rank, and role-in-theatre (uninjured). The sample does not include female participants due to the very few female United Kingdom military combat casualties in Afghanistan. Baseline assessments were conducted between 2015 and 2020, and the first follow-up was conducted between 2019 and 2023. The second follow-up is currently underway and due to be completed in 2026.