Among the tear cytokines examined, increased levels of pro-inflammatory cytokines (IL-1α, IL-6, IL-11, IL-12A, IL-15, IL-17A, and G-CSF), anti-inflammatory cytokines (IL-10), Th1 cytokines (IL-1β, TNF-α, and IFN-γ), Th2 cytokines (IL-4, IL-5, and IL-13), chemokines (CCL2, CCL4, CCL5, CCL11, CCL15, IL-8, CXCL9, and CXCL10), MMP-9, and others (ICAM-1 and TGF-β1) were observed in patients with schizophrenia. Here, IL4 is linked to schizophrenia.