For the first time, scientists have noted distinct differences between the brains and gene expression of men and women with severe depression, suggesting that doctors should look at the possibility of sex-specific treatments for certain mental health problems.
The research, published this week in the journal Biological Psychiatry, discovered that men and women with major depressive disorder (MDD) actually have opposite changes in the expression of 52 separate genes. While women had increased expression of genes affecting synapse function, men had decreased expression of the same genes. Equally, women had decreased expression of genes affecting the immune system, yet men experienced the opposite.
“This important paper highlights the divergent molecular mechanisms contributing to depression in men and women. It challenges the assumption that a similar diagnosis across people has the same biology," Dr John Krystal, Editor of Biological Psychiatry, said in a statement.
In a post-mortem procedure, the researchers dissected the brains of 50 people with major depressive disorder (26 men and 24 women) and compared them to the same number of unaffected brains. They focused on analyzing the three main brain regions that help regulate mood – the anterior cingulate cortex, dorsolateral prefrontal cortex, and amygdala – and that are dysfunctional in people with severe depressive disorders.
"While researchers have been examining the brains of depressed subjects for decades, many of these studies included only men," said lead author Dr Marianne Seney from the University of Pittsburgh.
It’s worth remembering that major depressive disorder affects women approximately twice as often as men and that women are three times as likely to have atypical depression. While this could be linked to a whole bunch of social, cultural, or environmental factors, this study also suggests there could be a molecular factor affecting the way depression manifests itself. Of course, the subjects were dead, so it was not possible for the researchers to see how these changes in gene expression affected them personally. Nevertheless, it certainly hints at the idea that sex-specific treatments could be a new avenue for researchers to explore.
"For instance, our results suggest that treatments to suppress immune function might be more appropriate for men with MDD, while treatments which boost immune function might be more appropriate for women with MDD," the study explains. "Alternatively, future treatments might aim to target the limited shared pathology present in both men and women with MDD."