Dr. Philip Sarrel, M.D.
Even though Premenstrual Syndrome (PMS) affects just about every woman at some point in their lives, doctors have up until now understood little about it. But new studies now point to a biological factor - hormones - as the principle cause for PMS.
The ovarian hormones oestrogen and progesterone are produced during each menstrual cycle. These hormones circulate in the blood stream, enter cells throughout the body, and affect how these cells are able to carry out their daily functions. The brain is made up of millions of cells that are sensitive to the effects of ovarian hormones and the fluctuations in these hormones during the menstrual cycle. For most women, ovarian hormones serve to support basic brain functions, including sleep and temperature control, sexual feelings, ability to reason and moods.
For many women, however, brain cell reaction to ovarian hormones can be negative; millions of women experience the monthly occurrence of PMS with irritability, anxiety and sadness during the week to 10 days preceding menstruation. PMS has been the subject of many scientific studies that have helped us to understand how ovarian hormones influence the workings of the brain. Ovarian hormones affect blood flow to the brain; they help sustain and promote the growth of brain cells that control the production and release of brain chemicals (neuro-transmitters), which are responsible for many different actions in the brain.
A recent study carried out at the National Institute of Mental Health found that PMS symptoms represent an abnormal response to normal hormone production levels. Women with severe symptoms were compared to women who did not have the syndrome. When the women with severe symptoms were treated with a drug that inhibited their ovaries from producing hormones, the symptoms decreased significantly. These women were also given a placebo, that is, a preparation that had no effects on their ovaries and did not contain any hormones. When they received the placebo, the symptoms were unaffected.
The women with PMS whose symptoms decreased when their ovaries were inhibited were then given the hormone-blocking drug, but this time they had either oestrogen or progesterone added. When either of these natural hormones was taken, the women had significant recurrence of their PMS symptoms. The women who did not suffer from PMS showed none of the reactions to the treatments that were seen in the PMS-affected women.
Thus, this study seems to clearly identify PMS as a disorder of abnormal sensitivity to normal levels of ovarian hormones. Symptoms such as sadness, anxiety and irritability, which occur in cycles relating to the time of menstruation, should be regarded as a biological disorder. Although the ovarian-blocking drug cannot be given indefinitely, it could be used for women with the most severe symptoms for at least a short time.
Over a longer period, women would suffer from the effects of inadequate levels of ovarian hormones, e.g., from bone loss and osteoporosis. However, the hormone-blocking drug helps define PMS as a condition caused by hypersensitivity to ovarian hormones. This new understanding of PMS may lead to new and better treatments.
