Our group has previously reported correlations between PTSD symptom severity and EV levels of neurofilament light chain (NfL), a protein found in large myelinated axons and a marker of axonal injury and degeneration in military populations with a positive history of mTBI (Menke et al., 2015; Zetterberg 2016; Guedes et al., 2020a). This evidence concerns the gene NEFL and post-traumatic stress disorder.