One study used in vivo stressed rats and performed a number of behavioral tests after giving them agarwood, and they found a strong antidepressant and anxiolytic effect of agarwood which they believed was due to inhibition and down regulation of a number of cytokines (IL-1α, IL-1β, and IL-6) that activate the HPA axis and eventually lead to depression and anxiety [127]. Here, IL6 is linked to depressive disorder.