I was emphasizing that premenstrual symptoms are physiological in nature. I fully agree that PMS is a physiological disorder. If there's anything we can educate people on, it's that PMS is physiological disorder that's caused by fluctuations in estrogen and progesterone. When estrogen starts to go down, you'll have a decrease in your serotonin receptors. When estrogen goes down, you have a decrease in serotonin transmission.
Estrogen decreases certainly affect serotonin transmission.
When progesterone goes up during that latter part of the cycle, it increases the metabolism of serotonin. So when progesterone goes up, serotonin goes down. So, yes, PMS could also be called serotonin deficiency syndrome. By all means, I don't want to imply ever that PMS is merely an attitude problem, or it's a matter that these weak-willed women have. It's a serotonin deficiency.