Women’s health is being put at risk because researchers have ignored gender differences in the brain out of fear of being labelled sexist, scientists have claimed.
Male and female brains can respond differently to drugs for conditions such as stroke, but for years neuroscientists have feared being “a pariah in the eyes of the neuroscience mainstream” if they highlighted the difference, according to a guest editor of a special edition of the Journal of Neuroscience Research.
Most early-stage research in neuroscience concentrates on men’s brains and assumes that the results can be generalised to women. This month the journal published an edition saying that there was clear evidence that gender “matters fundamentally, powerfully, and pervasively” and that the legacy of presuming otherwise has meant that women in particular have been badly served.
It highlighted research showing that the brains of the sexes differed from the level of individual synapses to the wiring of the entire brain.
Larry Cahill, a neurobiologist from University of California Irvine, said: “The assumption has been that, once you get outside of reproductive functions, what you find in males and females is fundamentally the same and therefore there is no reason to study both sexes — and beyond that it is not good to study females as they have pesky circulating hormones,” he said.
“The last 15 to 20 years has overwhelmingly proven that assumption is false, false, false.”
Typically, neuroscientists have concentrated on male brains for early research because women’s hormones fluctuate over their menstrual cycles and so their brains are considered harder to study. Professor Cahill said that studies into major diseases were being seriously hampered as a consequence.
An example is Alzheimer’s, in which a process of cell death called apoptosis occurs differently in men and women. “Stop and think about that for a second,” Professor Cahill said. “We are talking about experiments in petri dishes, and how cells die.
“If you are coming up with drugs to deal with that you’d damn well be aware of the differences.”
However, he said that pointing out such differences remained controversial. A vocal group of scientists has questioned the value of research into sex differences, arguing that they are not significant and can be a cover for legitimising sexism. Gina Rippon from Aston University has referred to some research as “neurosexism”.
“A key issue in this area is the large areas of overlap between the scores of males and the scores of females in almost any comparison you might compare to make, to the extent that you might be forgiven for thinking that, actually, the sexes are more similar than they are different,” she said. “A continued focus on sex as a binary category, with the consequent loss of focus on the rich sources of differences within rather than between groups, would seem to be a retrograde move.”
Professor Cahill, who said he had been warned off studying sex differences for fear that it would harm his career, said this was a misunderstanding. “They don’t get too upset about sex differences in the liver, heart, and microbiome,” he said. “Some people start to get itchy though when you talk about sex differences in the brain. That in turn stems from a deeply ingrained, powerful and false assumption.
“The heart of the resistance is the view that if neuroscience shows males and females are not the same in brain function, we are showing they are not equal. That is false.”
Another paper published in the journal argued that the status quo can adversely affect men, as well as women. It refers to Lazaroids, a stroke treatment that was rejected at the final hurdle because it no longer seemed to work. The authors have argued that it may well have worked — but only in men. This may have meant that at the final testing phase, when it was given to all patients, it appeared to lose half its efficacy and was wrongly rejected.
Eric Prager is the overall editor of the Journal of Neuroscience Research. He said that from now on the journal would accept submissions only if they clearly stated the sex of the subjects used, and justified the rationale. “I think more and more people are starting to agree that sex has to be considered in research,” he said. “The problem is that there are still some people that are against it completely, or that are unwilling to change.”
Gender differences? They’re not all in the head
Depression
Women have double the lifetime risk of depression. Preliminary research suggests that being depressed causes changes at the genetic level that are different depending on your sex.
Stress
Research implies that it can affect males and females differently, at both the behavioural and molecular level, and that different brain circuitry is involved.
Brain organisation
Differences in brain structure appear from an early age. A 2014 paper which looked at 1,000 brains found those of men had less communication between the two hemispheres and more within them. By carrying out a behavioural study on the same group, the authors suggested this change was reflected in better spatial memory for men and better word and facial memory for women.
Chronic pain
The majority of patients are women and studies have revealed increased pain sensitivity and lower pain tolerance among women. This may be due to the immune system’s interaction with the neurological system and that sex hormones cause this response to be very different in women.
Can you post the text of the article? It’s a register-to-play site. Not going to do that for one article.
Can you post the text of the article? It’s a register-to-play site. Not going to do that for one article.
Uintatherium 3 years, 2 months ago.
