NEW HAVEN, CONNECTICUT. Animal studies have shown that low brain levels of gamma-aminobutyric acid (GABA) are associated with depression. There is also evidence that some pharmaceutical drugs, which mimic the action of GABA, have potent mood-stabilizing and antidepressant properties. Now a team of researchers from the Yale University School of Medicine reports that GABA levels in the brains of depressed people are much lower than the levels found in healthy individuals. The study involved 14 depressed patients meeting DSM-IV criteria (eight men and six women) and 18 healthy controls (eleven men and seven women) none of whom were taking medications. The researchers measured the level of GABA in the occipital cortex region of the brain using a non-invasive proton magnetic resonance spectroscopy technique. They found that the mean GABA level in the brain of the depressed patients was less than half of that found in the healthy controls (0.71 mmol/kg vs. 1.48 mmol/kg). They also noted that women generally had higher GABA levels than men and that the levels tended to decline with age. The researchers urge further studies to confirm their findings and evaluate their possible therapeutic significance.
Sanacora, Gerard, et al. Reduced cortical gamma-aminobutyric acid levels in depressed patients determined by proton magnetic resonance spectroscopy. Archives of General Psychiatry, Vol. 56, November 1999, pp. 1043-47