TNF and major depressive disorder: This idea is consistent with our own work from the ALSPAC birth cohort which indicates that somatic symptoms mediate the association between IL-6 and psychological symptoms.23 Other groups have also reported that somatic symptoms of depression are associated with CRP, IL-6 and TNF-α levels.24 Therefore, somatic symptoms could be useful treatment target and marker of treatment response in clinical trials of anti-inflammatory treatment for depression.