GAD1 and major depressive disorder: Interestingly, AnyDep, MDD and GAD were nominally (P < 0.05) associated with a moderate decrease in the relative abundance of the glutamine and glutamate biosynthesis pathway, after adjustment for SSRIs or any PTDs (Tables S14 and S15; SRRIs and any PTDs: AnyDep: β=-0.1, SE = 0.04, Padj = 0.01; MDD: β=-0.1, SE = 0.05, Padj = 0.01; GAD: β=-0.1, SE = 0.03, Padj = 0.04).