GPX4 and major depressive disorder: Furthermore, there is mounting evidence that the processes underpinning this form of cell death, such as decreased glutathione and glutathione peroxidase-4 (GPx-4) levels, are involved in the pathogenesis and pathophysiology of BD [236, 237], schizophrenia [237–239] and MDD [237, 240] (review by reference [241]).