Women’s and men’s bodies and brains are different in almost every way, yet little scientific research has investigated the idea behind sex/gender-specific medicine. Until now.
One researcher making major contributions to the field is Canadian neuroscientist Dr. Liisa Galea.
A member of the Djavad Mowafaghian Centre for Brain Health and a Professor in the Department of Psychology at the University of British Columbia, Dr. Galea is interested in how biological sex hormones (meaning the physiological differences between male versus female sex hormones) affect brain health and behavior. Her findings are fascinating. Welcome, Prof. Galea.
Q&A with Dr. Liisa Galea
Q: The link between biological sex and brain health is an emerging area of study. What do we know so far?
A: We know that biological sex makes a difference in terms of brain health. For example, women are twice as likely to be diagnosed with depression than men, and we know that the majority of new Alzheimer’s cases are in women. The difference, however, isn’t just in the number of cases diagnosed but in how the disease manifests in each sex.
Depression symptoms, for instance, might be more severe in women than men, but women are also more likely to have anxiety associated with depression, while men are more likely to turn to alcohol or other substances in an effort to alleviate depression.
Women are also more likely to develop Alzheimer’s disease and show a steeper decline in memory after the onset of the condition compared to men.
There’s also data indicating sex differences in vulnerability to Alzheimer’s disease, depending on the genetic makeup of the individual. This data suggests that some diseases are more prevalent, and manifest differently in men than women. This is an understudied area of research and may lead to new findings that will influence treatment of disease.
Q: Why are women more susceptible to certain brain diseases than men?
A: This area of research is still growing and we don’t have all the answers yet. However, for depression specifically, if we look at the condition across a person’s lifespan, it’s clear that the ratio of women to men who suffer from depression is quite large during the reproductive years. What that means is women between the ages of 20 and 50-years old are at the highest risk of developing depression in their lifetime. Research suggests that reproductive hormones may be contributing to this greater vulnerability for depression.
We don’t yet know why women are more likely to be diagnosed with Alzheimer’s disease. Women live longer than men, so it’s thought that age is a likely contributor but research suggests that that is only one factor in the greater susceptibility in women to Alzheimer’s disease.
Q: In the course of your research, you discovered that childbearing results in marked alterations in a woman’s psychology and physiology. Tell us about your eye-opening findings.
A: Having children changes a woman in more ways than one. It may seem counter-intuitive, but a woman who has given birth to a child actually has lower levels of fluctuating hormones across her menstrual cycle compared to a women who has never given birth. This decades-long exposure to lower levels of hormones may have some repercussions on brain health.
We’re also starting to learn that after having four or more children, there appears to be more brain markers of Alzheimer’s disease. It also looks like it might be modulated by how many boys versus girls a woman gives birth to. Few research papers have been published on this topic, but what we know so far suggests that a woman’s brain is affected by whether or not she has had children.
Q: Let’s talk more about your work on Alzheimer’s and the brain. How is the brain affected?
A: Emerging data suggests that in early stages of Alzheimer’s, you’ll actually see an increase in neurogenesis (the growth of new brain cells) in an area of the brain called the hippocampus, rather than a decrease in neurogenesis which is what one might expect.
This may be the brain’s way of compensating for the loss of brain cells in other regions. But it’s important to understand that just because there’s new brain cells doesn’t mean that they’re forming the right connections to run the brain efficiently.
If we can figure out why the cells aren’t making the right connections, we can try to alter the brain chemistry so new neurons make the proper connections, repairing what was lost. I have high hopes that it’ll happen but it’s going take a several years to figure out.
Q: Mild cognitive impairment. Can the progression of symptoms slow down or be reversed?
A: This area of research is still growing, but early data suggests that a combination of controlled diet, physical activity and brain exercises can slow down mild cognitive impairment (MCI).
About 50% of people with mild cognitive impairment will go on to develop Alzheimer’s disease so it’s an important time to offset changes. When it comes to physical activity, both cardio and resistance training have been shown to improve memory in men and women with MCI.
The data, however, is mixed on the types of brain exercises someone with MCI should do. For example, playing Sudoku will help improve their Sudoku game, but not much else. Activities that require problem solving and decision making, and engage the person’s interest are more likely to keep their brain engaged. The more active and engaged a person with MCI is within different activities, the more likely that they’ll see some progress in terms of cognitive improvement.
Q: In the future, do you see a need for sex-specific treatments for certain diseases?
A: In my mind, that’s how it will have to be. There are already examples of how our specific chromosomal makeup or specific genes may be contributing to vulnerability or susceptibility to disease. Now we see that there are differences in men and women in how genetic makeup may influence susceptibility to disease, disease progress, and perhaps even treatments.
It’s complex but if it was simple, we would have figured it out already. I do think we’re making headway into need for sex-specific medicine and treatments in the future.
