TNF and post-traumatic stress disorder: Specifically, individuals with PTSD demonstrated as having higher levels of serum IL-1β [15,25], IL-6 [15,16,25,41,42,43,44,45,46,47], TNF-α [15,16,25,42,43,44,46,47,48], IFN-γ [15,47,49], and CRP [42,50] than individuals who have been exposed to trauma but have never developed PTSD.