For instance, the levels of proinflammatory cytokines such as interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor alfa (TNFα) are significantly increased in the blood of patients with posttraumatic stress disorder (PTSD) compared with both the control and patients with a history of injury without the development of PTSD symptoms [5]. Here, IL6 is linked to post-traumatic stress disorder.