Individuals with PTSD, or chronic psychological distress and traumatic life events more generally, exhibit higher levels of blood proinflammatory biomarkers such as interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and C-reactive protein (CRP), compared to healthy controls (Knight et al., 2021; Speer et al., 2018). Here, TNF is linked to post-traumatic stress disorder.