No links, but when I was experiencing severe mood plummets the entire week before my period, I had my hormone levels tested and my progesterone was very low at the time that it should be highest (around ovulation which is ~a week before your period if you're regular, which I am). My doc said to take Vitex every day and it made a huge difference, though it took about a month and a half to kick in. I took it for about 6 months straight, and then again later for a few months. I decided to wean off at the start of August to see if I still need it. So maybe I do, not sure. My last cycle started two weeks early, though I thought it was due to stress. I have no idea if that's what's going on now, but there's definitely a big link to depression/anxiety & candida overgrowth too.