Any disease in which pain is one of the main symptoms is always more frequent and more serious in women than in men. For example, in fibromyalgia, a disease characterized by chronic widespread pain of the musculoskeletal system, 90% of patients are women.

Is this difference due to the fact that women complain more about pain, as they are usually told, or that they really feel more pain than men and simply express it as they feel?

Attempts have been made to explain this striking gender imbalance with all kinds of theories. One of the most insistently proposed over time is based on the different role that women play in society, with marked differences in psychological, cultural, social or labor aspects that predispose women to have more diseases and more pain. That is to say, the old theory that they are the weaker sex and that is why they complain more about pain, among other things.

The problem is exacerbated because we do not have an instrument that allows us to measure pain objectively, that is, like a thermometer that tells us how far the pain reaches. To measure pain, we use questionnaires and scales in which the patient is asked how much pain she feels, and in any illness with pain, women’s scores are always higher than men’s.

In human experimental models of pain, in which painful stimuli are applied and responses to them measured, women also show a stronger response to these stimuli than men.

As to experimentation with animals, in which the supposed socio-cultural role that has always been talked about does not exist, female mice react to painful stimuli in a more intense way than males and, in addition, the behavior they develop dealing with pain is also different.

What has been measured in mice is the biological response of the animals when subjected to painful stimuli, and what has been seen is that it is indeed different in both sexes. Here I am not going to describe these differences in detail, but I will say that several molecules such as some cytokines, brain peptides and neurotransmitters related to the response of the nervous system to stimuli behave differently depending on the sex of the individual.

From these findings it can be deduced that, if the pathophysiological mechanisms are different in both sexes, the sensation of pain will also be different. In this way, when women  show a higher pain score than men, it is not because there are socio-cultural differences, but because they are actually feeling more pain.

This has to make us reflect to change our way of evaluating what women tell us about their pain. We must not continue to be anchored in the classic interpretation that her pain is less important because she is a woman.

For example, we can start by measuring the pain of men and women on different scales, because we currently use the same measurement scale for both sexes and, what is worse, we then apply it to the tools we use to assess the severity of a disease.

The immediate consequences are that women with diseases where pain is an important symptom always turn out to be more serious than men and therefore more tests are done, they are given more energetic and aggressive treatments and they also undergo more surgical interventions. This action inevitably leads to women always having more complications, more side effects from drugs and responding worse to treatment.

This bias when it comes to measuring the intensity of some symptoms is not only detrimental to women. Returning to the example of fibromyalgia, we can ask ourselves why there are so few men with this disease. The answer is possibly because men feel less pain and since the current diagnosis of fibromyalgia is based precisely on pain, men are not so easily diagnosed, even if they have the same disease.