MAPT and schizophrenia: In contrast, total tau levels did not differ significantly between patients with BD and healthy controls (SMD = -0.07, 95% CI: [-0.26, 0.12]), Data were insufficient to support a meta-analysis of the relationship between phosphorylated tau and BD.<h4>Conclusion</h4>T-tau and p-tau protein levels are lower in schizophrenia patients compared with healthy controls, whereas no significant difference was observed in BD patients.