These two treatments are obviously different, but they both point to an entirely new chemical axis in the brain that could be targeted to treat depression: the glutamine/glutamate axis. Commonly abbreviated Glx, these chemicals are suppressed in people with severe depression and post-traumatic stress disorder (PTSD) and do not increase when patients take serotonin-targeting antidepressants. The company I lead is working to develop drugs to raise Glx without the damaging side effects of ketamine or ECT. The science is promising: The FDA recently issued a biomarker letter of support, its first in psychiatry under the 21st Century Cures Act, recognizing that an increased level of Glx correlates with decreased levels of depression and that drugs targeting Glx are linked to a reduction in depression and suicidal ideation. - www.washingtonpost.com