Research questions the prudence of attributing negative moods to the menstrual cycle.
"The idea that any emotionality in women can be firstly attributed to their reproductive function -- we're skeptical about that," Dr. Sarah Romans told me, skeptical said with audible restraint.
She and eight other researchers at the medical school at the University of Toronto published a review last week in the journal Gender Medicine that looked at all of the clinical research they could find to date on PMS with prospective data. Their conclusion was that the articles, in aggregate, "failed to provide clear evidence in support of the existence of a specific premenstrual negative mood syndrome."
Romans isn't saying that the mood symptoms we attribute to PMS aren't real and common. But she is saying that those symptoms are culturally over-attributed to the menstrual cycle, to the detriment of the medical community and those experiencing them -- and as a broader issue of gender equality.
The Diagnostic and Statistical Manual of Mental Disorders, which is the definitive text of U.S. psychiatrists, defines and outlines a diagnosis called premenstrual dysphoric disorder (PMDD). It's often casually defined as a severe version of PMS, which itself is not included in the DSM as a diagnosis. PMDD is characterized by physical and behavioral symptoms in the second half of the menstrual cycle.
"I do believe that PMDD exists," Dr. Romans told me. "I think we still don't know the prevalence. There was a good study recently that measured the prevalence rate down from 3-9 percent to around 1.5 percent." Still, "it's doing any woman a disservice to not let her have access to some of the effective treatments for PMDD." She describes how effective anti-depressant SSRIs like sertraline (Zoloft) can be, immediately, for PMDD.
Romans specifies, "Our interest was really in the wider premenstrual syndrome construct. I think most would assume that PMS is much more firmly evidence-based than in fact it is."
In their paper they note that the menstrual cycle has "historically been the focus of myth and misinformation, leading to ideas that constrain women's activities." An association between negative mood and the menstrual cycle has a long history, first noted in the scientific literature in 1931 by gynecologist Robert Frank and psychoanalyst Karen Horney. Long before that there was the wandering womb -- the notion, in the teachings of Hippocrates, that illness was due to the uterus moving around the body like a wild beast. The word hysteria is even derived from the Greek hystera, meaning uterus.
A broad mood-somatic premenstrual syndrome (PMS) was actively promoted by Katharina Dalton in the United Kingdom during the post-World War II years; she implicated progesterone deficiency as its cause. During the 1960s, PMS gradually supplanted Frank's earlier term of "premenstrual tension," and PMS continues to be the common term in the developed world. However, the definition of PMS, whether referring to mood alone or mood plus physical symptoms (e.g. bloating), is not clear when the term is used in both the scientific literature and in lay discussions.
The University of Toronto team systematically reviewed all the major English-language research that included daily mood reports that had been collected prospectively for at least one full menstrual cycle. There ended up being 41 that they considered large enough to be valid.
According to their review process, 15 studies (36.6 percent) "found no association" between mood and the phase of one's menstrual cycle. Another 17 (41.5 percent) "found an association of negative mood in the premenstrual phase, combined with another phase of the menstrual cycle." Six (13.5 percent) found an association between "negative mood and the premenstrual phase." The remaining 4 studies (8.5 percent) found an association between negative mood and a non-premenstrual phase. So, of the published research, several large studies have found associations between various phases of the menstrual cycle and moods. But they vary as to which phase. And sometimes no relationship exists at all.
The review doesn't discount the organic nature of cyclic moods, but it does suggest that hormonal fluctuations related to the menstrual cycle aren't definitively or regularly to blame. And "when there is a menstrual cycle tie-up," Romans explains, "it's actually perimenstrual -- the premenstrual (3-5 days before menstruation) and the menstrual phases together -- not purely premenstrual."
Romans' team is working on more research that compares menstrual cycle with other social and health variables in terms of what most determines mood, under the hypothesis that it's heavily weighted toward the latter. "The menstrual cycle signal was very small in terms of explaining the negative moods we were studying," she explains.
"I think this can be seen as the modern day equivalent of the old wandering womb notion," she told me, "that women are hysterical because of their reproductive system. And when a woman's upset, it's still often one of the first thoughts people have -- maybe she's premenstrual -- rather than 'Is her physical health bad? Is she under a lot of stress? Is she lacking social support?'"
"I go beyond that in my own thinking, which is that the whole PMS notion serves to keep women non-irritable, sweet, and compliant the rest of the time. There is a range of paradoxes -- world-turned-upside-down events -- like festivals, Mardi Gras, where people are socially prescribed to behave out of role. In Europe in medieval times there'd be one day a year where the lord would serve his own servants and workers, and then the rest of the time it's the other way, servant obeying the master. And these kinds of rituals serve to embed the normal behavior. I think PMS is a bit like that. 'We'll let you be cranky and bad-tempered now, but just for one or two days. The rest of the time you've got to be like a true woman.' Of course that's pretty feminist and hard to get data for, but at times I think it explains quite a lot."
Gender biases color the discussion in both directions, if unconsciously, but at least this study can inform more research on how we can keep everyone in the best mood possible, firstly by not overlooking pathology out of cultural expectation.
"PMS has been called a culture-bound syndrome in North America, and there are huge cultural differences in terms of how readily that explanation is reached for." There aren't, to her knowledge, cultures where a notion of PMS isn't a consideration, but there are many where the basics of the cycle are being re-evaluated.
"There's an anthropologist called Beverly Strassman who studied African tribes and has made the point that monthly menstruation is a very modern phenomenon. Women used to have later menarche, more pregnancies, longer periods of breast-feeding -- so in all they'd probably have half the number of menstrual cycles. Compared to modern women who have around 400 cycles during an active reproductive life. So there are important basic questions that remain unanswered. Is it healthy to have monthly menses? We really don't know."
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