Table 1.
The relationship between major depressive disorder and GABA concentration measured by magnetic resonance spectroscopy
| Brain region | Comparison groups | Direction | Reference |
|---|---|---|---|
| OCC | 14 medication-free depressed versus 18 healthy controls | Down | 20 |
| OCC | 33 depressed subjects versus 38 healthy controls | Down | 19 |
| OCC | 6 depressed subjects versus 12 healthy controls | Down | 17 |
| OCC | 15 treatment-resistant depressed versus 24 healthy controls | Down | 18 |
| OCC | 15 treatment-resistant depressed versus 18 non-treatment-resistant depressed | Down | 18 |
| OCC | 18 non-treatment-resistant depressed versus 24 healthy controls | NC | 18 |
| OCC | 15 recovered depressed versus 18 healthy controls | Down | 27 |
| OCC/ACC | 12 recovered depressed versus 11 healthy controls | Down | 28 |
| OCC | 11 depressed subjects, before and after SSRI treatment | Up | 22 |
| OCC | 8 depressed subjects, before and after ECT treatment | Up | 23 |
| OCC | 15 medication-free depressed subjects, before and after CBT (8 subjects completed experiment) | Trend down | 26 |
| ACC | 15 treatment-resistant depressed versus 24 healthy controls | Trend down | 18 |
| ACC | 15 treatment-resistant depressed versus 18 non-treatment resistant depressed | Trend down | 18 |
| ACC | 18 non-treatment-resistant depressed versus 24 healthy controls | NC | 18 |
| Dorsal PFC | 20 depressed patients (medication-free for 4–8 weeks) versus 20 healthy controls | Down | 21 |
| Dorsal PFC | 16 recovered depressed subjects versus 15 healthy controls | NC | 24 |
| VM PFC | 20 depressed patients (medication-free for 4–8 weeks) versus 20 healthy controls | NC | 21 |
| VM PFC | 16 recovered depressed subjects versus 15 healthy controls | NC | 24 |
Abbreviations: ACC, anterior cingulate cortex; CBT, cognitive behavioral therapy; ECT, electroconvulsive therapy; NC, no change; OCC, occipital cortex; PFC, prefrontal cortex; SSRI, selective serotonin-reuptake inhibitor; VM, ventromedial.