Researchers at the University of Pittsburgh and the Centre for Addiction and Mental Health (CAMH) in Toronto, Canada, discovered that men and women with major depressive disorder (MDD) experience opposite genetic transformations. This study “Opposite Molecular Signatures of Depression in Men and Women,” which is published in Biological Psychiatry, suggests that men and women require different treatment techniques for depression.

“While researchers have been examining the brains of depressed subjects for decades, many of these studies included only men,” explained lead author Marianne Seney, PhD, of University of Pittsburg, as reported by NeuroscienceNews. John Krystal, MD, Editor of Biological Psychiatry, adds that these findings show there are indeed pathological differences in a man and woman’s diagnosis: “This important paper highlights the divergent molecular mechanisms contributing to depression in men and women.”

To reach these findings, the research team analyzed eight different published datasets, four of which consisted only of men and four of which consisted only of women. More specifically, they looked at gene expression levels—which signify how much protein is being produced by a given gene—in postmortem brain tissue of 50 people in total. They also looked at 50 postmortem brains (again, 26 men and 24 women), which weren’t affected by MDD.

The researchers observed altered gene expressions, but they typically occurred in only men or only women. However, the altered gene expressions that were observed in both men and women were changed in reversed direction. For example, men showed decreased expression of genes affecting synapse function, while women had increased expression of the same genes; in another instance, men showed increased expression in genes affecting immune function, while women had decreased expression.

Analysis took place in three different brain regions, which all work to regulate mood and fail to function properly in MDD: the anterior cingulate cortex, the dorsolateral prefrontal cortex, and the amygdala. And while observing each of these regions proved to show how gene expression differs in men and women with MDD, the researchers were not able to study how these variations affect the two genders differently (because it was postmortem brain tissue that they looked at). Still, this study made significant findings and opened the door for additional research.

Approximately twice as many women are affected by MDD than men are. Furthermore, women are three times more likely to experience atypical depression and suffer from hypersomnia and weight gain. These differences suggested that MDD may differ on the molecular level as well and motivated the researchers to explore the possibility, which proved worthwhile. According to Dr. Seney, “these results have significant implications for development of potential novel treatments and suggest that these treatments should be developed separately for men and women.”

Resources:
Elsevier (2018, March 14). Men and Women Have Opposite Genetic Alterations in Depression. NeuroscienceNews. Retrieved March 14, 2018 from http://neurosciencenews.com/genetics-sex-differences-depression-8631/

Seney, M. L., Huo, Z., Cahill, K., French, L. et al. (2018, January 17). Opposite Molecular Signatures of Depression in Men and Women. Biological Psychiatry. Retrieved on March 14, 2018 from http://www.biologicalpsychiatryjournal.com/article/S0006-3223(18)30065-9/fulltext