Atagün, M. İ.Şıkoglu, M. E.Soykan, Ç.Can, S. S.Ulusoy-Kaymak S.Çayköylü, A.Algın O.Phillips, M. L.Öngür, D.Moore, C. M.2018-04-122018-04-1220170304-3940http://hdl.handle.net/11693/37353The aim of this study is to measure GABA levels of perisylvian cortices in schizophrenia and bipolar disorder patients, using proton magnetic resonance spectroscopy (1H-MRS). Patients with schizophrenia (n = 25), bipolar I disorder (BD-I; n = 28) and bipolar II disorder (BD-II; n = 20) were compared with healthy controls (n = 30).1H-MRS data was acquired using a Siemens 3 T whole body scanner to quantify right and left perisylvian structures’ (including superior temporal lobes) GABA levels. Right perisylvian GABA values differed significantly between groups [χ2= 9.62, df: 3, p = 0.022]. GABA levels were significantly higher in the schizophrenia group compared with the healthy control group (p = 0.002). Furthermore, Chlorpromazine equivalent doses of antipsychotics correlated with right hemisphere GABA levels (r2= 0.68, p = 0.006, n = 33). GABA levels are elevated in the right hemisphere in patients with schizophrenia in comparison to bipolar disorder and healthy controls. The balance between excitatory and inhibitory controls over the cortical circuits may have direct relationship with GABAergic functions in auditory cortices. In addition, GABA levels may be altered by brain regions of interest, psychotropic medications, and clinical stage in schizophrenia and bipolar disorder. � 2016 Elsevier Ireland LtdEnglishAuditory cortexBipolar disorderGABAMagnetic resonance spectroscopySchizophrenia4 aminobutyric acidatypical antipsychotic agentlithiumvalproic acid4 aminobutyric acidneuroleptic agentadultArticleauditory cortexbipolar disordercontrolled studyfemalehumanmajor clinical studymaleneurotransmissionpriority journalproton nuclear magnetic resonanceright hemisphereschizophreniasuprasylvian gyrustemporal lobebipolar disorderdrug effectsmetabolismmiddle agednuclear magnetic resonance spectroscopyproceduresschizophreniayoung adultAdultAntipsychotic AgentsAuditory CortexBipolar DisorderFemalegamma-Aminobutyric AcidHumansMagnetic Resonance SpectroscopyMaleMiddle AgedProton Magnetic Resonance SpectroscopySchizophreniaTemporal LobeYoung AdultArticle10.1016/j.neulet.2016.11.051