The symptomatology of depression has also been linked to various metabolites and molecules (e.g., fatty acids, magnesium ions, and thyroid hormones), omega-3 polyunsaturated fatty acid deficiency has been associated with depression and suicidal behaviors [36, 37], and patients with depression have reduced serum magnesium and zinc levels [38] as well as reduced synthesis and secretion of thyroid hormones [39]. The gene discussed is TG; the disease is major depressive disorder.