These authors contributed equally to this manuscript.
Brain gamma-aminobutyric acid (GABA) abnormalities in bipolar disorder
Version of Record online: 2 MAY 2013
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Volume 15, Issue 4, pages 434–439, June 2013
How to Cite
Brain gamma-aminobutyric acid (GABA) abnormalities in bipolar disorder. Bipolar Disord 2013: 15: 434–439. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd., , , , , , , .
- Issue online: 3 JUN 2013
- Version of Record online: 2 MAY 2013
- Manuscript Accepted: 2 JAN 2013
- Manuscript Received: 22 JUL 2012
- Department of Psychiatry of Harvard Medical School. Grant Number: K23MH079982
- anterior cingulate cortex;
- bipolar disorder;
- GABA ;
- magnetic resonance spectroscopy;
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.
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.
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.
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.