BDNF and depressive disorder: Specifically, we asked whether: (1) promoter IV-BDNF deficiency caused depression-like behavior in juvenile (ED) and old adult mice of both genders; (2) antidepressive EET effects differed among the three life stages or between genders; (3) the EET effects endured after 1 month; and (4) EET effects on BDNF expression correlated with the behavioral effects.