Prof. Gregory Oxenkrug, MD [Pavlov Medical Academy (1965)], PhD [1970], St. Petersburg, Russia. Major contributions to the field: 1). Serotonin-kynurenine hypothesis of major depressive disorder [Lapin & Oxenkrug, Lancet,1969, Citation Classic]; 2). Prolongation of Drosophila melanogaster span by genetic or pharmacologic inhibition of tryptophan–kynurenine pathway [The sixth most cited publication of Journal of Neural Transmission in 2010]; 3). Anthranilic acid hypothesis of cognitive impairment in neurodegenerative disorders and aging [2024]; 4). Discovery of anti-hypertensive effect of melatonin (1986), and antidepressant and antiaging effects of N-acetyl-serotonin, an immediate melatonin precursor (1998). Academic appointments: Professor of Psychiatry at Tufts University, Boston, MA (1994 - present), Professor at Brown and Wayne State Universities. He was Chairman, Department of Psychiatry, St. Elizabeth's Medical Center, Brighton, MA (1994-2005); and Chief, Psychiatry Service, VA Hospital, Providence, RI (1988-1994). Prof. Oxenkrug is a Fellow of American, Canadian and International Colleges of Neuropsychopharmacology