title: Perisylvian GABA levels in schizophrenia and bipolar disorder.
abstract: The 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 3T 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.
authors.affiliation: Department of Psychiatry, Ankara Yıldırım Beyazıt University Medical School, Ankara, Turkey; Department of Psychiatry, Ankara Ataturk Training and Education Hospital, Ankara, Turkey. Electronic address: miatagun@ybu.edu.tr.
authors.forename: Murat İlhan
authors.initials: Mİ
authors.lastname: Atagün
authors.affiliation: Department of Psychiatry, University of Massachusetts Memorial Medical School, Memorial Campus 119 Belmont Street, Worcester, MA 01605, USA.
authors.forename: Elif Muazzez
authors.initials: EM
authors.lastname: Şıkoğlu
authors.affiliation: Department of Psychiatry, Ankara Yıldırım Beyazıt University Medical School, Ankara, Turkey; Department of Psychiatry, Ankara Ataturk Training and Education Hospital, Ankara, Turkey.
authors.forename: Çağlar
authors.initials: Ç
authors.lastname: Soykan
authors.affiliation: Department of Psychiatry, Ankara Yıldırım Beyazıt University Medical School, Ankara, Turkey; Department of Psychiatry, Ankara Ataturk Training and Education Hospital, Ankara, Turkey.
authors.forename: Can
authors.initials: C
authors.lastname: Serdar Süleyman
authors.affiliation: Department of Psychiatry, Ankara Ataturk Training and Education Hospital, Ankara, Turkey.
authors.forename: Semra
authors.initials: S
authors.lastname: Ulusoy-Kaymak
authors.affiliation: Department of Psychiatry, Ankara Yıldırım Beyazıt University Medical School, Ankara, Turkey; Department of Psychiatry, Ankara Ataturk Training and Education Hospital, Ankara, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Çayköylü
authors.affiliation: Department of Radiology, Ankara Atatürk Training and Education Hospital, Ankara, Turkey; National Magnetic Resonance Imaging Research Center, Bilkent University, Ankara, Turkey.
authors.forename: Oktay
authors.initials: O
authors.lastname: Algın
authors.affiliation: Department of Psychiatry, Pittsburgh University Medical School, Pittsburgh, PA, USA.
authors.forename: Mary Louise
authors.initials: ML
authors.lastname: Phillips
authors.affiliation: Psychotic Disorders Division, McLean Hospital, Belmont, MA, USA; Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
authors.forename: Dost
authors.initials: D
authors.lastname: Öngür
authors.affiliation: Department of Psychiatry, University of Massachusetts Memorial Medical School, Memorial Campus 119 Belmont Street, Worcester, MA 01605, USA; Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA.
authors.forename: Constance Mary
authors.initials: CM
authors.lastname: Moore
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology; D001303:Auditory Cortex / Q000187:drug effects / Q000378:metabolism; D001714:Bipolar Disorder / Q000378:metabolism*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods; D012559:Schizophrenia / Q000378:metabolism*; D013702:Temporal Lobe / Q000187:drug effects / Q000378:metabolism; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D014150:Antipsychotic Agents; D005680:gamma-Aminobutyric Acid
keywords: Auditory cortex; Bipolar disorder; GABA; Magnetic resonance spectroscopy; Schizophrenia