A more recent study by Li and colleagues (2018) showed that in a chronic mild stress mouse model of depression and anxiety, there was a reduction in Lactobacillus species, and an increase in the inflammatory markers IFN-γ, TNF-α, and indoleamine 2,3-dioxygenase-1 levels in the hippocampus. The gene discussed is IFNG; the disease is depressive symptom measurement.