Effects Of Electroconvulsive Therapy On GABAergic System In Schizophrenia

Background As a most effective therapeutic method for psychiatric disorders,electroconvulsive therapy(MECT)is of intriguing interest as its mechanism remains unclear.Previous ECT studies mainly focused on major depressive disorder(MDD)and found increased levels of?-aminobutyric Acid(GABA)after MECT treatment.Abnormalities of GABAergic interneurons are associated with schizophrenia evidenced by post-mortem,neuroimaging and transcranial magnetic stimulation(TMS)studies.In this study,we aimed to find out whether ECT could mediate GABAergic system leading to remission of psychotic symptoms in schizophrenia.Methods 48 hospitalized patients fulfilling the diagnostic criteria for schizophrenia(DSM-IV)were included and divided into two groups by their treatment strategy.One is MECT group consisting of 21 patients who received brief pulse bitemporal electrical stimulation thrice weekly together with antipsychotic drugs.The other is drug group consisting of 27 patients who only received antipsychotic drugs.Another23 healthy sex/age-matched healthy controls were included.For all patients,medial prefrontal GABA concentrations were quantified by 1H-proton magnetic resonance spectroscopy(MRS)at baseline and after 4-week treatment,as well as cortical inhibition indicators tested by TMS.Healthy controls only scanned at baseline.20patients finished MRS and 6 finished TMS in DRUG group,which in MECT group the numbers were 17 and 8 separately.And 22 healthy controls finished TMS test.Results 1.Baseline:GABA+/Cr in schizophrenia patients were lower than healthy controls.CSP was found to be a longer in patients while SICI was lower when compared with healthy controls.2.After treatment:There was an increasing trend of GABA+/Cr in both DRUG and MECT group and the increasing effect was significant through MECT.However patients treated effectively got no GABA augment in MECT group.SICI seemed to be enhanced in MECT group.And both groups got same therapeutic efficacy.3.Correlation analysis:After treatment,increase of GABA+/Cr in MECT group has inversely correlation with positive/negative score reducing rate(pearson r=-0.583,p=0.029;spearman r=-0.568,p=0.034).Conclusion1.Compared to healthy controls,schizophrenia patients were supposed to have GABAergic impairment for lower GABA+/Cr,longer CSP and weaker SICI.2.The increasing effects on GABA+/Cr indicated that there were some similar therapeutic mechanisms of MECT and antipsychotic drugs,however,the different relationships between change of GABA and therapeutic effect suggested something different.MECT's antipsychotic effect was not related with GABA increasing,and it may exert impact by strengthening SICI through GABA_A receptor system.