Similar to the results of the few studies that have been conducted to assess the impact of SSRIs on inflammatory mediators in human subjects (43, 44), studies with a predator-exposure animal model for PTSD showed that pharmacotherapy with the SSRI, sertraline, lessened the levels of the pro-inflammatory mediator IL-1 and signaling through the pro-inflammatory receptor TLR4 in the CNS, while increasing the CNS levels of anti-inflammatory cytokines IL-4 and IL-10 (53). Here, IL4 is linked to post-traumatic stress disorder.