TNF and post-traumatic stress disorder: Studies reported that individuals with PTSD are characterized by altered levels of C-reactive protein (CRP) (Eraly et al., 2014; Michopoulos et al., 2015; Lindqvist et al., 2017; O'Donovan et al., 2017; Miller et al., 2017) and peripheral cytokines, including, IFN-γ (Hoge et al., 2009; Lindqvist et al., 2014), interleukin-1β (IL-1β) (Passos et al., 2015), interleukin-6 (IL-6) (Lindqvist et al., 2017; Passos et al., 2015; Imai et al., 2018; de Oliveira et al., 2018) and tumor necrosis factor alpha (TNF-α) (Bruenig et al., 2017).