MAOB and schizophrenia: Second, because of the limitations of the MAO-B–detecting PET method, this study could only provide indirect evidence of reactive astrocytes in schizophrenia pathophysiology, as in previous animal, postmortem brain, and neuroimaging studies.13,21,23,40 Further studies with direct methods to investigate astrocytes in patients with schizophrenia are warranted to confirm the role of reactive astrocytes in the pathophysiology of schizophrenia.