M161. NEURAL CHANGES INDUCED BY ELECTROCONVULSIVE THERAPY (ECT) IN SCHIZOPHRENIA PATIENTS: A SYSTEMATIC REVIEW

BACKGROUND: Despite the remarkable progress of antipsychotic drugs, electroconvulsive therapy (ECT) remains a potent treatment option for schizophrenia. However, the underlying neural mechanism of ECT effect on schizophrenia remains unclear. For this reason, we reviewed literature which investigated structural and functional brain changes after ECT in schizophrenia patients. METHODS: We searched the PubMed, EMBASE, Cochrane Reviews database to search for eligible articles. Following medical subject headings (MeSH) terms were used: ECT AND schizophrenia AND (MRI OR MRS OR PET OR SPECT OR NIRS OR DTI). RESULTS: Thirteen studies were eligible for the reviewing process. Of them, three studies investigated the effect of ECT upon volumetric changes of cerebral regions; 4 studies on the effect of ECT upon functional brain activities; three studies using magnetic resonance spectroscopy (MRS); and another three studies investigating blood flow changes. Medial temporal lobe (MTL) structures seemed to be increased after ECT sessions in schizophrenia patients, as in major depressive disorder (MDD) patients. Insula and left dorsolateral prefrontal cortex (DLFPC) is other potential neural substrates that might be disease specific for ECT induced changes in schizophrenia. Outcomes of functional imaging seemed to vary among studies, with divergent region of interests (ROI). MRS study results suggests the ratio of left prefrontal NAA/Cr might be increase after adequate ECT sessions. Studies investigating effect of ECT upon cerebral blood flow largely varied among studies with mixed results. DISCUSSION: Despite the treatment effect of ECT in schizophrenia patients, there have been only a handful of studies investigating the biological mechanisms underlying ECT. Of them, the effect of ECT in schizophrenia seemed also to be mediated by structural volume increases in the MTL region (as in MDD), and the insula and left DLPFC might be other potential neural substrates of ECT effect in schizophrenia patients. Future studies are needed to validate the neural mechanisms that underlie the effect of ECT in schizophrenia, which might help to aid in tailoring treatment plans for refractory schizophrenia patients.