IDO1 and major depressive disorder: What’s interesting is that the IL-Iβ plasma levels in patients with temporal lobe epilepsy and depression are significantly higher than the levels in the people for temporal lobe epilepsy without depression, it has verified that there is positive correlation between IL-1 β level and depression (79) owing to that the rise of IL-1β in chronic temporal lobe epilepsy further upregulates Indoleamine 2,3-dioxygenase1 (IDO1) expression to increase the kynurenine/tryptophan ratio and ruduce the serotonin/tryptophan ratio in the hippocampus (80).