Editor's note: David is Skepchick's resident Answer Guy. Each month, he'll explore the answers to your questions. For his first challenge, he found a worthy topic on the Skepchick forum: what exactly is PMS? To ask a question, e-mail him at answerguy@skepchick.org.

“Sounds like a case of the Mondays.” A commonly held conception of PMS might conjure up an image something like this: If an over caffeinated upbeat waiter had made the above remark to a woman diner with PMS, instead of to a disaffected male cubicle drone, then he would likely have found that his 37 pieces of flair had suddenly been caused to migrate from his suspenders to his lower intestinal region.

PMS, as any adult who has not been living in a Tibetan monastery for the past fifty years knows, is shorthand for Premenstrual Syndrome. Men fear it, women loathe it. It can make life miserable for both. Nevertheless, despite its seeming ubiquity, there is mystery and misunderstanding surrounding PMS. That suggests it is high time we take a critical look at it.

How many women get PMS, what exactly is it, when can we expect it, what causes it, how does a woman know if she has it, and what is the best treatment for it? I went looking for answers to those questions and discovered that finding them is not as simple and pat as I expected. What I found prompted me to divide this article into two parts, this first one examining only the first three of my six questions.

Prevalence of PMS
First, here are some numbers: 1) 20 to 40 percent of all women of childbearing age suffer from at least some premenstrual difficulties; 2) 75 to 80 percent of women experience premenstrual difficulties in their lifetime; and 3) the majority (about 95 percent) of women of childbearing age experience some symptoms of premenstrual syndrome. Well, it seems the numbers are inconclusive and contradictory, as they differ not only with respect to the portion of a woman’s life examined, but also with respect to whether even a majority of women in their childbearing years exhibit any indications of PMS. The figures above come from the American College of Obstetricians and Gynecologists, Coolnurse.com, and the UK’s National Health Service, respectively. Visit other web sites discussing the topic, and you are likely to encounter various other estimates of the prevalence of PMS. The New York Times approaches the subject with an especially open mind, reporting recently that the proportion of women of relevant age suffering from PMS is between 20 and 90 percent. Using a highly technical weighted average formula (the details of which I will not bore you with here), I calculated a precise figure: a lot of women PMS (the term PMS is not only a noun, but also a verb, as in, “Stay the hell away from Rebecca; she’s PMSing” – ed. note: it occurs to me that I may not get this published unless I slip it in at the last minute and the editor neglects to proofread or edit it, or I send her copious amounts of rich, exotic chocolate).

Defining PMS
What is Premenstrual Syndrome, anyway? A single definitive answer is elusive, but the NHS states that it is “a collection of physical, psychological and emotional symptoms related to your menstrual cycle.” By definition it is a recurring condition. PMS can cause not only physical pain and discomfort, but also significant adverse effects on a woman’s interpersonal relationships at work and at home. Wikipedia explains that a syndrome is a set of several clinically recognizable symptoms which occur together and are associated closely with one another such that the presence of some symptoms alerts a physician to suspect and investigate the possible presence of others.

The NHS notes that there are up to 150 different symptoms which have been linked to PMS, but some of the most common ones include the following:

* Feeling irritable and bad tempered
* Headaches
* Feeling depressed
* A general feeling of being upset or emotional
* Difficulty sleeping
* Difficulty concentrating
* Feeling full and ‘bloated’
* Backache
* Breast tenderness or swelling
* Some weight gain (up to 1 kg)
Other sources also list these common symptoms:
* skin blemishes or acne;
* swelling of hands and feet;
* nausea or constipation, followed by diarrhea at the onset of menstruation;
* increased thirst or appetite;
* a craving for certain foods—especially sweets (e.g., chocolate) and items high in salt;
* increased irritability or mood swings;
* fatigue;
* forgetfulness or confusion;
* feelings of anxiety or loss of control;
* sadness or uncontrolled crying.
* a noticeable change in libido.

Apparently, several major systems in the body not directly related to the reproductive system can be affected by the monthlies, including the digestive, circulatory, nervous, endocrine, and dermatologic systems. Some authorities state that sufferers of PMS may experience any combination of the above symptoms, within a wide range of degrees of severity, from mild to overwhelming, and they can be debilitating to about five to ten percent of women who experience PMS. Paying careful attention to the previous sentence may lead one to conclude that perhaps conflating PMS with PMS symptoms contributes to widespread disagreement about the prevalence of PMS among the relevant population of women.

It is important to note that not every woman who experiences one or more symptoms associated with PMS actually suffers from the more serious syndrome itself. That may be one reason there are such varying estimates of the prevalence of PMS; some reports might be conflating having one or more common symptoms of PMS with having the larger syndrome itself. Another possible reason is the difficulty individuals who report having PMS may have in differentiating between having the syndrome and merely experiencing one or more of its symptoms. Finally, the nebulous nature of any syndrome and the absence of any bright line test for it likely contribute to the difficulty of rendering a definitive diagnosis of PMS, leading to further uncertainty about its prevalence.

Also important to consider is that many of the common symptoms of PMS can be caused by other conditions, disorders, or illnesses not related to a woman’s menstrual cycle. Therefore, an incorrect diagnosis of PMS may in fact lead a patient and her physician to disregard the possibility that she may be suffering from some other underlying disorder. It is even possible that a correct diagnosis of PMS could mask another unrelated disorder or medical condition. When in doubt, therefore, it is best to seek competent medical advice and care. What you don’t know can hurt you.

PMS is not associated with and should not be confused with severe cramps or very painful periods (dysmenorrhea). Pain severe enough to limit normal activities accompanies menstruation or even precedes it slightly in about 40% of menstruating women, causing about 10% of them to be incapacitated for up to three days. It is the leading cause of absenteeism from work or school for women of childbearing age, but dysmenorrhea is not part of PMS.

In order to gain a less clinical and more colorful, visceral understanding of PMS, I asked a female friend to explain it to me. She was eager to help and extended this offer, “I’ll punch you in the gut, slam your chest with a bat, smack you upside your head, have you run up 300 stairs, several times, and shove a broomstick up your ass. There now, I think that’ll reasonably compare to what it feels like. Your gut will hurt, your chest will be sore, your legs will feel weak, and you'll feel like no one gives a shit when you’re bleeding from your ass.” I politely declined.

History of PMS
Given that Premenstrual Syndrome is a widely experienced and far reaching health problem, it is astonishing to discover that most medical practitioners did not take PMS or its many associated symptoms seriously enough to study them in much depth until just decades ago. Hippocrates, the father of Western medicine, noted as early as 370 B.C.E. that, “Women are subject to intermittent agitations which make their way from the head to the uterus whence they are expelled.” Nevertheless, it was not until 75 years ago that Western medical doctors began to recognize and study Hippocrates’ “agitations” collectively as a serious medical syndrome. Before that, physicians tended to minimize the seriousness of many of the symptoms we recognize today as component parts of PMS by placing them under the broad umbrella of “hysteria,” perhaps reflecting or even supporting the then prevailing chauvinistic view of women as “the weaker sex.” Victorian era physicians in England and the U.S. often treated hysteria by massaging a woman patient’s genitals until the patient reached orgasm. Perhaps it was a hysterical Victorian woman who first coined the phrase, “Is there a doctor in the house?”

In 1931, American physician Dr. Robert T. Frank presented his landmark paper “Hormonal Causes of Premenstrual Tension” to the New York Academy of Medicine, and thus began a new era of taking seriously what we now call PMS. Two decades later, two British physicians, Drs. Katherine Dalton, and Raymond Greene, published “The Premenstrual Syndrome” in a 1953 edition of British Medical Journal, coining the modern phrase and making theirs the first official PMS paper in medical literature. The behavioral symptoms associated with PMS, which seem to get the most attention in depictions of it in modern popular culture, were first formally recognized by psychiatrists and psychologists in 1987, when the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) listed an extreme and severe form of them as Late Luteal Phase Dysphoric Disorder (LLPD). That diagnosis was modified and renamed Premenstrual Dysphoric Disorder (PDD) with the 1994 publication of the DSM-IV, supplanting its predecessor, the DSM-III. The diagnostic feature that most distinguishes PDD from other severe emotional or mood disorders found in women is its cyclical nature concurrent with the appropriate phase of the menstrual cycle. In recent years, the pharmaceutical industry, much more so than the medical profession, has led scientific research into the biomedical causes of and effective treatments for severe behavioral symptoms associated with PMS. Evidently, pharmaceutical giants are betting big on the efficacy of drug treatments for the behavioral symptoms of PMS and the willingness of physicians to prescribe them and patients to accept them.

Modern Controversy
Remarkably, there exists a recent controversy in some academic circles about whether PMS actually is a biomedical disorder. Some feminist scholars offer an alternative model for PMS, positing that it is a culture-bound syndrome. They propose that a woman’s using the behavioral aspects of PMS to her advantage is possibly a means for Western women to reject unrealistic expectations placed upon them by a patriarchal society. This alternative model downplays the physiological pathologies associated with PMS and seems implausible in light of the surfeit of empirical evidence that its symptoms are cyclical and concurrent with a women’s menstrual cycle. I submit that it is highly likely that few medical doctors or biomedical researchers in the field give any serious consideration to the feminist model for PMS described above, or to any other non-biomedical alternative explanations for PMS. Therefore, for purposes of this article, this writer will assume the biomedical model to be valid and leave the debate about other possible explanations for PMS for others to ponder.

Timing of PMS
When can one expect PMS symptoms to appear in its sufferers? This question is probably the easiest to answer. Never one to shy away from stating the obvious, I submit that the key to unlocking this mystery is the term “premenstrual.” Premenstrual of course refers to the occurrence of the symptoms in the luteal phase, or second half, of a woman’s menstrual cycle. This is after the release of an egg (ovulation), which delineates the boundary between the follicular phase of the cycle and the luteal phase. The luteal phase ends when the woman’s period begins (menstruation). PMS symptoms might last from about three to 14 days, but they stop at the beginning of a woman’s period. After Aunt Flo’s visit, a woman may then experience a symptom-free week from about Day 7 to Day 14 of her cycle. Below is a chart depicting the typical 28-day menstrual cycle for a normal healthy woman in her childbearing years:

Source: Wikipedia

Here is some free advice to men and other partners of women of childbearing age. Pay attention to your female partner’s cycle. Give her little gifts and do thoughtful little things to soothe and comfort her in that sometimes difficult luteal phase. Doing so might make life easier and more joyful for both of you.

Next: In Part Two we will explore possible causes of PMS, how a proper diagnosis is made, and some currently available treatments for it; as a bonus, we will examine the question of whether over the counter products marketed specifically as treatments for some symptoms of PMS are more effective than similar products marketed for general use.

David McGehee is an attorney by trade, but a scientist and skeptic by nature. In his spare time David enjoys reading, watching movies, listening to music, going to the gym, and playing guitar. He admires skepchicks. If you have a question you'd like him to answer here in Skepchick, e-mail him at answerguy@skepchick.org.

ISSUE 3 CREDITS

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Darcie Hodgkins Langone, Lynette Davidson, David McGehee, Ben Radford, Michael McRae, Matthew Armstrong

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