|“Current research indicates that PMS is triggered by the effects of ovarian hormones on the brain, which in turn influences multiple brain-body systems and leads to a wide variety of symptoms.”|
What Is PMS?
By Elizabeth Lee Vliet, MD
Medical Definition of PMS (Premenstrual Symptoms)
A pattern of recurring mood, behavioral, and physical symptoms which regularly occurs between ovulation and menstruation and abates by the end of menstruation, to be followed by a symptom-free interval each month. Symptoms are present for at least six months, cause moderate to severe disruption in normal functioning, and are not due to another disorder.
PMS Symptom Clusters
What Causes PMS?
Current research indicates that PMS is triggered by the effects of ovarian hormones on the brain, which in turn influences multiple brain-body systems and leads to a wide variety of symptoms.
Many researchers believe that PMS involves a neuroendocrine imbalance. The underlying mechanism involves neuroendocrine triggers within the hypothalamus and pituitary, which in turn affect neurotransmitter function.
The diverse symptoms of PMS are caused by the many different brain centers and the whole series of neuropeptide hormones governed by these neurotransmitters. The neuropeptides beta-endorphine and MSH not only regulate the neurotransmitters involved in mood and behavior, they also modulate the release of other hormones affecting physical states and moods. The brain-body regulation of progesterone and estrogen in response to these changes in neuropeptides differs from woman to woman, which probably accounts for the various clinical forms of PMS. As better designed studies are done, I think we will find that hormone ratios and rate of change are key factors in PMS.
The clear pattern of hormone profiles in my patients is one of low estradiol and relatively normal levels of progesterone, so that there is a reduced ratio of estradiol to progesterone. I view PMS as a neuro-endocrine disorder beginning with hormone shifts that affect multiple brain centers. The brain events then trigger a variety of physical changes in multiple systems in the body, and can be aggravated by diet, substance use, and life stress.
There are other postulated causes of PMS, but I think these may also be results of neuroendocrine changes, so it is unclear whether some of these disturbances are causes of the syndrome, or are results of alterations in the reproductive hormone levels. These include:
Other factors that may be involved in the rising incidence of PMS are:
Extensive, detailed information on PMS and its treatment is available in Chapter 7 of Screaming to Be Heard.