NEFL and post-traumatic stress disorder: Guedes et al. (63) found that in both plasma and extracellular vesicles from service members with TBI + PTSD, NfL was elevated compared to TBI-only samples (extracellular vesicles: d = 0.86, 95% CI: 0.47, 1.25; plasma: d = 0.67, 95% CI: 0.29, 1.06).