IL17A and Anxiety: Although, several studies implicated the role of Th1 cytokine (IL-1β, IL-2, IL-12, TNF-α, and IFN-γ) and Th2 cytokines (IL-4, IL-6, IL-10) in the pathophysiology of different anxiety and depressive disorders1,44, only a very few studies were performed investigating the role of Th17 cytokines (IL-17, IL-22, IL-21) and Th17 cytokine stimulant, IL-23 in the pathogenesis of GAD.