Causes of PMS
Scientists have been unable to identify a single cause of PMS. Theories range from hormonal and chemical to nutritional and psychological. Women whose mother or sisters have PMS are more likely to have it, so there may be a genetic component. A combination of genetic, physiological, and environmental causes are likely.
Hormones and Neurochemicals & PMS
The physical, emotional, and psychological changes that occur in PMS coincide with hormonal changes of the menstrual cycle. PMS may be a response to declining levels of estrogen and progesterone that occur just prior to menstruation. The exact role of the various hormones are not clear. Some neurochemicals (chemicals that help make up the nervous system) also have been implicated. Hormones and neurochemicals may interact to produce PMS.
Mineralocorticoids are a group of hormones that regulate the body's fluids and electrolytes (e.g., sodium, potassium). Changing levels of mineralocorticoids may cause the bloated feeling that is common in women with PMS.
Prolactin stimulates breast development and the formation of milk during pregnancy and is associated with amenorrhea (abnormal absence of menstruation) and other gynecologic complications. Excess prolactin may cause the breast tenderness associated with PMS, although studies show that suppressing the secretion of excess prolactin does not relieve symptoms.
Prostaglandins are hormonelike substances that play a role in the luteal phase of the menstrual cycle, which occurs prior to bleeding. Changing levels of prostaglandins may be involved in PMS.
Serotonin and gamma-aminobutyric acid (GABA) are chemicals that relay signals from one nerve cell to the next (neurotransmitters). Low levels of serotonin have been linked to depression, and low levels of GABA are associated with anxiety, both symptoms of PMS.
Endorphins are neurochemicals that suppress pain and increase the threshold to painful stimuli. Low levels of endorphins may be involved in PMS.
Nutrition & PMS
Nutrition probably plays a causal role in PMS. Women can alleviate many symptoms by changing their diet. Eliminating certain foods or drinks often reduces symptoms to more tolerable levels.
Hypoglycemia (low blood sugar) afflicts many PMS sufferers. Some researchers speculate that the hypoglycemia is a precursor to PMS.
Depression & PMS
Because depression-related symptoms are prevalent in women who suffer PMS, there may be an underlying psychological condition that causes or contributes to PMS. Approximately 60 percent of women with major depressive disorder (e.g., depression) also have PMS, and more than 30 percent of women who suffer chronic depression experience their first depressive episode during a time of significant hormonal change (e.g., premenstrually). In one study, between 57 and 100 percent of women who suffered PMS were found to have had at least one prior major depressive episode, compared to 0 to 20 percent of women without PMS.
However, PMS encompasses more than depression, and by focusing too much on this aspect, other important physiological factors may be overlooked.