We used the Revealing Individual Susceptibility to a PTSD-like phenotype (RISP) model to behaviorally classify male rats as resilient or susceptible before trauma and tested their serum and prefrontal cortical (mPFC) levels of IL-1β, IL-6, TNFα, IL-10, IFN IFNγ, and KC/GRO to determine whether inflammation represents a putative susceptibility factor for PTSD. Here, IL6 is linked to post-traumatic stress disorder.