Since the stress responsive HPA axis has been implicated in the pathophysiology of depression, several studies have shown modulating effects of SJW extracts on HPA axis function in rats such as a reduced gene expression of genes that control HPA axis function (Butterweck et al. 2001a; b) as well as decreased plasma adrenocorticotropic hormone (ACTH) and corticosterone levels in stressed rats (Butterweck et al. 2001a; b). This evidence concerns the gene POMC and major depressive disorder.