Consistently, pioglitazone, a PPAR-γ agonist, has been reported to reduce depressive symptoms in MDD patients with metabolic syndrome, particularly among those with elevated CRP levels (Kemp et al., 2014), and to improve affective and motivational deficits when added to standard therapy in bipolar depression (Sepanjnia et al., 2012). This evidence concerns the gene PPARG and major depressive disorder.