ECT-induced brain plasticity correlates with positive symptom improvement in schizophrenia by voxel-based morphometry analysis of grey matter

Electroconvulsive therapy (ECT) is often considered as an augmentation of antipsychotic treatment for schizophrenia in drug-refractory cases. However, the mechanisms underlying the observed therapeutic effects are still not understood.We aimed to investigate changes in whole brain grey matter volume (GMV) before and after modified ECT. GMV was determined using voxel-based morphometry (VBM) whole brain analysis. Correlations of brain structural changes with clinical improvement were also investigated.Twenty-one schizophrenia patients treated with a full course of ECT combined with antipsychotics (ECT group) and 21 schizophrenia patients treated only with antipsychotics (Drug group) were observed in parallel. Magnetic resonance imaging scans were performed at baseline (T1) and follow-up (T2) for each patient. Data were compared to a healthy control group (HC group) of 23 persons who were only scanned at baseline. Demographic data were matched between the three groups.Significant interactions of group by time were found within four brain regions: the left parahippocampal gyrus/hippocampus, right parahippocampal gyrus/hippocampus, right temporal_pole_mid/superior temporal gyrus, and right insula. Post-hoc analysis revealed an increase of GMV across all four regions amongst ECT group, but a decrease of GMV within the Drug group. Furthermore, the ECT group showed a significant positive correlation of GMV change in the right parahippocampal gyrus/hippocampus with a reduction of positive subscore in the positive and negative syndrome scale. Both treatment groups did not differ significantly in terms of GMV from the HC group in these regions either at T1 or at T2.Our findings indicate that ECT may induce brain plasticity as indexed by grey matter volume change during the treatment of schizophrenia via distinct mechanics from those by antipsychotic medications. ECT may ameliorate the positive psychotic symptoms of patients suffering from schizophrenia by preferentially targeting limbic brain areas such as the parahippocampal gyrus/hippocampus.