A meta-analysis of cytokine alterations in schizophrenia found that cytokine levels vary with clinical status. IL-1β, IL-6, and TGF-β were state markers, increasing during acute exacerbations and normalizing with antipsychotic treatment. In contrast, IL-12, IFN-γ, TNF-α, and sIL-2R were trait markers, remaining elevated in exacerbations and after treatment. No significant difference in IL-6 levels was found between stable outpatients and controls. CSF IL-1β was significantly lower in schizophrenia patients. The study highlights the potential of cytokines as biomarkers for acute relapse and treatment response. However, most studies lacked control for confounding factors like BMI and smoking. The findings support immune-cytokine hypotheses for schizophrenia, with evidence for macrophage-T-lymphocyte and microglial theories. The study also suggests that cytokine levels may normalize after antipsychotic treatment, indicating their role as state markers. Despite these insights, the results should be interpreted cautiously due to study heterogeneity and limited control for confounding variables. Future research should focus on cytokine networks and their role in schizophrenia's pathophysiology.A meta-analysis of cytokine alterations in schizophrenia found that cytokine levels vary with clinical status. IL-1β, IL-6, and TGF-β were state markers, increasing during acute exacerbations and normalizing with antipsychotic treatment. In contrast, IL-12, IFN-γ, TNF-α, and sIL-2R were trait markers, remaining elevated in exacerbations and after treatment. No significant difference in IL-6 levels was found between stable outpatients and controls. CSF IL-1β was significantly lower in schizophrenia patients. The study highlights the potential of cytokines as biomarkers for acute relapse and treatment response. However, most studies lacked control for confounding factors like BMI and smoking. The findings support immune-cytokine hypotheses for schizophrenia, with evidence for macrophage-T-lymphocyte and microglial theories. The study also suggests that cytokine levels may normalize after antipsychotic treatment, indicating their role as state markers. Despite these insights, the results should be interpreted cautiously due to study heterogeneity and limited control for confounding variables. Future research should focus on cytokine networks and their role in schizophrenia's pathophysiology.