Understanding sex differences in the brain is vital to mental health

WE’VE heard it all. Male brains are bigger and better at spatial awareness. Female brains are geared to multitasking and emotional intelligence. Stereotypes of how sex influences behaviour abound, and as increasingly sophisticated brain-scanning techniques appear, more claims of such disparities have come to light.

But, as we discover in our special feature on the human brain (“Your amazing brain: 10 challenging questions that highlight brilliant new discoveries about the human brain”), trying to identify a biological reason for population differences in men’s and women’s behaviours, interests and occupations is a nuanced debate that encompasses gender as well as sex, and is in no way settled.

Nevertheless, we should continue to try. Not least because if there really are sex-based brain differences, it would have huge implications for our health. That’s because many medical conditions involving the brain and neurodivergence affect the sexes at different rates and in different ways. For instance, women have higher rates of depression, anxiety and eating disorders. Men have higher rates of autism and attention deficit hyperactivity disorder.

There could be many reasons for these skewed sex ratios: autism may be being underdiagnosed among girls or they may manifest typical behaviours differently, for example. Likewise, depression may be higher in women due to biological factors, because women tend to earn less money or because men are less likely to seek help for mental health problems.

But there could also be sex-based brain differences. If there are, the picture still isn’t complete. These might not be due to direct genetic influences or the effects of sex hormones, but could stem from the way society generally treats men and women differently throughout life.

Unravelling all of this could shed light on the mechanisms behind these conditions, leading to better treatment strategies. Ultimately, then, it is an endeavour that isn’t about pitting male and female brains against each other, but one that has the potential to help everybody.