A major breakthrough in brain science is shedding new light on the biology behind depression. Using advanced imaging, researchers have found that people with major depressive disorder have significantly lower levels of Activity of energy, glutamate, and glutathione metabolism enzymes in blood cells of elderly patients with depression European Journal of Psychiatry Prefrontal Glutathione Levels in Major Depressive Disorder Are Linked to a Lack of Positive Affect Glutathione: Benefits and Supplements