We often hear women say that their mothers had headaches or were bad-tempered before their periods, and add that it was not referred to as PMS then, of course. It is tempting to assume that PMS can be inherited. However, there are also a lot of women who remark that their mothers are unsympathetic because they themselves never had any trouble before periods. So what does this mean?
On their own, these comments are not significant. We don’t all have the same eye colour as our mothers and that is genetically inherited. Half our genes come from our fathers. We may inherit different genes for the same characteristic. For example, we may inherit blue eyes from one parent and brown eyes from the other. In this example brown eyes develop because although the form of the gene for blue eyes is present, it has no effect. The form of the gene for brown eyes is said to be dominant.
If two people who have inherited both forms of the gene for eye colour marry, some of their children could be blue eyed because they have inherited the form of the gene that makes blue eyes from both parents. This is the end of the digression into the genetics of eye colour, and I haven’t even mentioned green or grey eyes. Inheritance is rarely simple and how people look and their surroundings, as well as their genes affect how they behave.
European women who lie in the sun go brown, but they do not give birth to brown babies because of their sunbathing. The effects of the environment are not inherited. Some women tan more easily than others and this ability can be passed on to their babies. The kind of skin a person has depends on both genes and surroundings.
Do fat children inherit their tendency to put on weight from fat parents, or do fat parents tend to overfeed their children? It is hard to tell.
So what is the case for PMS? Does it depend on the genes or events during a girl’s life, or what she is brought up to expect, or a combination of these and other factors?
Since it is impossible to have the same person reared twice under different conditions, and unethical to experiment on people by asking them to have babies together just to see if the girls grow up to have PMS, it is difficult to find out. Clues can be found here and there is the literature of medicine and social studies. Asking lots of questions might offer pointers, and twin studies are useful.
In 1977 Weissman and Klerman compared the incidence of depression in men and women as it was described in the medical literature. Their review went back over forty years. They admitted that the apparent greater frequency of depression in females might be accidental due to the way symptoms were reported. Alternatively, the difference could be real and due to biological susceptibility such as genetic effects or female hormones, or psychological factors like social discrimination or female-learned helplessness. There were no firm conclusions here.
Two researchers called Ghadirian and Kamaraju published a report in 1987 in which they suggested that a subgroup of the women who have mood swings which are related to the menstrual cycle might go on to have serious psychiatric disorders and that these might be genetically predetermined (my italics). This was based on a study of only three women and the tone of the article was very much of the “we must bear this in mind” variety.
Taghavi studied three generations of women who had PMS. There were eleven in all. Seven were successfully treated with amitryptaline, a tricyclic antidepressant. His report, published in 1990 stated that there was a possibility of a genetic predisposition in some forms of PMS especially where depression was a symptom. This was still a very small sample on which to base a conclusion.
More recently (1996) Gruber, Hudson and Pope reviewed the literature about a group of conditions that all have treatment-resistant depression, and which seem to be on the border between psychiatry and other branches of medicine. PMS was one such condition. Others were fibromyalgia, chronic fatigue syndrome (ME), migraine, irritable bowel syndrome and atypical facial pain. They were interested in the fact that chemically different groups of antidepressants could all be used to treat this group of disparate conditions. They argued that it was unlikely to be that these medicines were all helping just the symptoms of the different disorders by chance. It was more likely that the disorders were themselves related to each other in their cause that was possibly genetic.
They urged caution however, because like so many other authors who have attempted to combine the results of many studies, they found that there was little consistency in experimental design, diagnostic criteria and methods for measuring the experimental outcome. The doses of antidepressants used varied. Sometimes other treatments were used at the same time. Studies did not always assess both psychological and physical symptoms.
All the studies mentioned so far need more than a pinch of salt.
Research into human genetics often involves twins. Identical twins have the same genes. They are naturally occurring clones. If they are brought up separately then it might be possible to distinguish the effects of genes and surroundings. Fortunately for the twins, this happens rarely. Even so, if there are greater similarities in a particular feature between identical twins than non-identical twins, then it is more likely that the similarities are due to genetic constitution.
Kendler, Silberg, Neale, Kessler, Health and Eaves investigated the symptoms experienced in the premenstrual and menstrual phases by 827 pairs of female twins.
Statistical analysis of their findings suggested that premenstrual and menstrual symptoms were independent of one another, but both were thought to have some genetic causes. They were also thought to be independent of neurotic symptoms. The genes, which predispose to Premenstrual Symptoms appears to be largely distinct from those that predispose either to menstrual or neurotic symptoms.
This seems conclusive. There was a large sample of twins. Unfortunately only relatively few symptoms were retrospective self reports. It is a well-known difficulty with PMS research that after a month or two, women do not remember accurately what symptoms they have had nor how serious they were. Consequently it is necessary to make a daily record of their experience of PMS from the beginning of the study. This is called prospective recording.
Another twin study was the subject of an article published in 1993 by a researcher called Condon. 157 identical twins 143 non-identical twins completed the questionnaires. The results suggested that there are several genes, which affect PMS. This is like human height. There are several genes that affect how tall a person will be in good conditions. Each gene can exist in a dominant from which confers tallness or in a form that confers shortness. Height will vary according to whether one or several genes of the dominant form are inherited. Condon concluded that in PMS there seemed to be several genes that influenced whether a woman developed the condition. Each gene existed in more than one form and it was the combination of the forms inherited that determined if she had PMS.
That seems to be straightforward. However there were two other explanations for the same results. Identical twins shared greater environmental similarities than non-identical twins, Condon stated. He also thought that PMS might be a reflection of underlying neuroticism that was genetically inherited.
There have been many articles arguing whether PMS and other more serious mental disorders are related. Does one cause the other? Do they have the same cause? Are women who have PMS more likely to have a family history of mental instability? And so on. That could be the basis of another article for NAPS News.
The most recent work published about twins was by van den Akker, Eves, Stein and Murray in 1995. They investigated the genetic and environmental factors affecting PMS, depression and a general neuroticism trait. From statistical analysis of results from a large group of twins, they concluded that there was a genetic contribution to personality, but not to PMS symptom reporting in particular.
Just when it seemed there might be something definite to write about PMS, we have to admit that we are not sure yet. Finding out about PMS is like trying to grasp a greased pig. Genetic factors may be part of the cause of PMS or they may not. All that can truthfully be said is that they can’t be ruled out entirely on the evidence so far.