In the PTSD ≤ 5 y group (current diagnosis lasting 5 years or less), biomarker inter-correlations were moderate, with glutamine–glutathione (ρ = 0.44, p = 0.011) weaker than in the No PTSD group, and caspase-1–BDNF showing a weak negative association (ρ = −0.19, p = 0.28), while glutamine–BDNF exhibited a moderate negative correlation approaching significance (ρ = −0.31, p = 0.083), potentially reflecting interactions between glutamatergic and neurotrophic pathways in recent PTSD (Table 2). Here, BDNF is linked to post-traumatic stress disorder.