TNF and post-traumatic stress disorder: Studies in literature have also observed high levels of various cytokines that are raised in patients infected with SARS-CoV-2, such as IL-6, TNF-α, IL-1β and ferritin in patients with psychiatric disorders such as depression, post-traumatic stress disorder (PTSD) and obsessive–compulsive disorder (OCD) (Ma et al., 2010; Parker et al., 2015; Lindqvist et al., 2017; Karagüzel et al., 2019).