Table 1

Studies included in analyses of plasma GABA level

StudyDiagnostic statusDisorder statenFemale sex, %Mean age, yrMain results
Petty et al. (39)Unipolar and bipolarCurrent MDE29NANADiminished GABA in unipolar disorder, no change in bipolar disorder
Petty et al. (40)UnipolarCurrent MDE16NANADiminished GABA
Petty et al. (41)Unipolar and bipolarCurrent MDE113NANADiminished GABA
Petty et al. (42)UnipolarCurrent MDE77044.7Diminished GABA
Petty et al. (43)BipolarCurrent MDE33NA41.2Diminished GABA
Paige et al. (38)Older adults with unipolar MDECurrent MDE94467.4Diminished GABA
Lu et. al (36)Melancholic unipolar MDECurrent MDE2748NADiminished GABA
Berrettini et al. (51)BipolarEuthymic10NA35Diminished GABA
Berrettini et al. (52)BipolarEuthymic494435–39Diminished GABA in bipolar patients without lithium
Palmio et al. (49)UnipolarBefore/after treatment107056No GABA level change after ECT
  • ECT = electroconvulsive therapy; GABA = γ-aminobutyric acid; MDE = major depressive episode; NA = not available.