Zhen Tang (14) found that serum levels of CRP, IL-1α, IL-2, IL-6, IL-8, IL-12, IFN-γ, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were significantly higher in the GAD group compared to the control group, while Vogelzangs found (31) no associations with IL-6 or TNF-a in anxiety disorders including GAD. Here, TNF is linked to generalized anxiety disorder.