Pace et al. (2006) reported increased NF-κB DNA-binding as well as increased IL-6 in otherwise-healthy male patients, a finding that independently correlated with the severity of major depression. Several other studies have also found increased cerebrospinal fluid (CSF) levels of IL-6 in MDD patients and suicide attempters (Lindqvist et al., 2009; Sasayama et al., 2013). This evidence concerns the gene IL6 and major depressive disorder.