title: Brain gamma-aminobutyric acid (GABA) abnormalities in bipolar disorder.
abstract: OBJECTIVE
  Gamma-aminobutyric acid (GABA) abnormalities have been implicated in bipolar disorder. However, due to discrepant studies measuring postmortem, cerebrospinal fluid, plasma, and in vivo brain levels of GABA, the nature of these abnormalities is unclear. Using proton magnetic resonance spectroscopy, we investigated tissue levels of GABA in the anterior cingulate cortex and parieto-occipital cortex of participants with bipolar disorder and healthy controls.
  
  
  METHODS
  Fourteen stably medicated euthymic outpatients with bipolar disorder type I (mean age 32.6 years, eight male) and 14 healthy control participants (mean age 36.9 years, 10 male) completed a proton magnetic resonance spectroscopy scan at 4-Tesla after providing informed consent. We collected data from two 16.7-mL voxels using MEGAPRESS, and they were analyzed using LCModel.
  
  
  RESULTS
  GABA/creatine ratios were elevated in bipolar disorder participants compared to healthy controls [F(1,21) = 4.4, p = 0.048] in the anterior cingulate cortex (25.1% elevation) and the parieto-occipital cortex (14.6% elevation). Bipolar disorder participants not taking GABA-modulating medications demonstrated greater GABA/creatine elevations than patients taking GABA-modulating medications.
  
  
  CONCLUSIONS
  We found higher GABA/creatine levels in euthymic bipolar disorder outpatients compared to healthy controls, and the extent of this elevation may be affected by the use of GABA-modulating medications. Our findings suggest that elevated brain GABA levels in bipolar disorder may be associated with GABAergic dysfunction and that GABA-modulating medications reduce GABA levels in this condition.
authors: Department of Psychiatry, Beth-Israel Deaconess Hospital, Salt Lake City, UT, USA; Department of Psychiatry, Harvard Medical School, Salt Lake City, UT, USA; Department of Psychiatry, Massachusetts Mental Health Center, Boston, USA; Psychotic Disorders Division, McLean Hospital, Belmont, MA, USA.
authors: Roscoe O
authors: RO
authors: Brady
authors: Julie M
authors: JM
authors: McCarthy
authors: Andrew P
authors: AP
authors: Prescot
authors: J Eric
authors: JE
authors: Jensen
authors: Alissa J
authors: AJ
authors: Cooper
authors: Bruce M
authors: BM
authors: Cohen
authors: Perry F
authors: PF
authors: Renshaw
authors: Dost
authors: D
authors: Ongür
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006179:Gyrus Cinguli / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D058027:Neuropsychiatry; D010296:Parietal Lobe / Q000378:metabolism / Q000473:pathology; D011569:Psychiatric Status Rating Scales; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D005680:gamma-Aminobutyric Acid
keywords: GABA; MEGAPRESS; anterior cingulate cortex; bipolar disorder; magnetic resonance spectroscopy
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