An animal experiment using Bifidobacterium breve to improve depressive symptoms in mice found that Bifidobacterium breve CCFM1025 could significantly alleviate HAP axis hyperactivity, inhibit hypothalamic corticotropin releasing factor (CRF) secretion, and reduce serum corticosterone levels (42).Hyperactivity of the HPA axis also leads to increased levels of inflammation in patients with depression (49).Jang et al. This evidence concerns the gene CRH and major depressive disorder.