GSK3B and major depressive disorder: In an independent study, the C-carriers of the -50T/C SNP responded better to lithium augmentation in acutely depressed, antidepressant-resistant BP and MDD patients [122]; however, Szczepankiewicz et al., [123] did not find a significant association between the –50T/C SNP and GSK3β response to prophylactic lithium in BP.