Table 3

Studies included in analyses of magnetic resonance spectroscopy GABA level

Study	Diagnostic status	Disorder state	n	Female sex, %	Mean age, yr	ROI	Voxels size, mL	Main results
Sanacora et al.10	Unipolar	Current MDE	14	43	42.9	OCC	13.5	Diminished GABA
Kugaya et al.8	Unipolar	Current MDE	6	0	36.2	OCC	11.1	Diminished GABA
Sanacora et al.9	Unipolar	Current MDE	33	NA	41.9	OCC	13.5	Diminished GABA
Epperson et al.14	Postpartum unipolar	Current MDE	9	100	30	OCC	20.5	Trend for enhanced GABA
Hasler et al.30	Unipolar	Current MDE	20	65	34	VMPFC & DA/dmPFC	18 and 30	Diminished GABA in DA/dmPFC, no change in vmPFC
Price et al.15	Unipolar	Current MDE	33	39	42.2	OCC & ACC	18 and 18.75	Diminished GABA in resistant MDE, no change in nonresistant MDE
Walter et al.13	Unipolar	Current MDE	17	58	40	ACC	17.5	No GABA level change
Murrough et al.17	Unipolar	Current MDE	31	47.6	39.1	OCC & ACC	18 and 18.75	No GABA level change
Gabbay et al.16	Unipolar	Current MDE	20	60	16.7	ACC	18.75	Diminished GABA in anhedonic MDE, no change in nonanhedonic MDE
Abdallah et al.11	Unipolar	Current MDE	23	70	43	OCC	13.5	No GABA level change
Godlewska et al.12	Unipolar	Current MDE	33	42	29.9	OCC	10	No GABA level change
Wang et al.18	Bipolar	Current MDE & Euthymic	29	52	34.4	OCC & mPFC	18 and 12.5	No GABA level change
Hasler et al.29	Unipolar	Euthymic	16	75	41	VMPFC & DA/dmPFC	18 and 30	No GABA level change
Shaw et al.27	Unipolar	Euthymic	19	100	21	OCC	27	No GABA level change
Kaufman et al.54	Bipolar	Euthymic	13	38	40	Basal ganglia	NA	No GABA level change
Brady et al.22	Bipolar	Euthymic	14	43	33	POC & ACC	16.7 and 16.7	Enhanced GABA level
Godlewska et al.23	Bipolar	Euthymic	13	54	24	OCC & mPFC	10 and 6.75	No GABA level change
Sanacora et al.25	Unipolar	Before/after treatment	11	36	39	OCC	13.5	Enhanced GABA after SSRI
Sanacora et al.24	Unipolar	Before/after treatment	8	38	46	OCC	13.5	Enhanced GABA after ECT
Sanacora et al.26	Unipolar	Before/after treatment	8	NA	NA	OCC	20.5	No GABA level change after CBT
Valentine et al.28	Unipolar	Before/after treatment	10	60	42	OCC	13.5	No GABA level change after ketamine
Abdallah et al.20	Unipolar	Before/after treatment	28	63	42	OCC	13.5	No GABA level change after CBT
Godlewska et al.12	Unipolar	Before/after treatment	27	42	30	OCC	10	No GABA level change after SSRI

ACC = anterior cingulate cortex; CBT = cognitive behavioural therapy; DA/dmPFC = dorsoantero/dorsomedial prefrontal cortex; ECT = electroconvulsive therapy; GABA = γ-aminobutyric acid; MDE = major depressive episode; MRS = magnetic resonance spectroscopy; mPFC = medial prefrontal cortex; NA = not available; OCC = occipital cortex; POC = parieto-occipital cortex; ROI = region of interest; SSRI = selective serotonin reuptake inhibitor; vmPFC = ventromedial prefrontal cortex.