Biomarker–PSQI-A correlations were uniformly weak and non-significant (e.g., glutamine with PSQI-A: Total: ρ = 0.13, p = 0.48; caspase-1 with PSQI-A: Trauma NM: ρ = 0.13, p = 0.49; BDNF with PSQI-A: Total: ρ = −0.23, p = 0.20), indicating minimal direct influence of these biomarkers on sleep disturbances in chronic PTSD. This evidence concerns the gene BDNF and post-traumatic stress disorder.