Magnetic Resonance Spectroscopy Studies of GABA in Neuropsychiatric Disorders

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervoussystem and is integral to managing brain excitability. GABA concentrations vary according to age,gender, and brain region. Magnetic resonance spectroscopy (MRS), with editing or with localized2-dimensional chemical shift methods, can measure GABA levels in vivo, ex vivo, or in vitro, particularlyat ultra-high magnetic field strengths. Proton (¹H) MRS studies have found reduced or abnormalGABA concentrations in several neuropsychiatric disorders, including epilepsy, anxiety disorders,major depression, and drug addiction. Disorders with low GABA levels may be treated by augmentationof GABAergic function, such as by medications that block the degradation or reuptake ofGABA. Examples of such a rational therapeutic approach include anticonvulsants that elevate brainGABA levels and are effective for the treatment of epilepsy and anxiety disorder.