One recent study made a staggering discovery, in that depression differs between male and female. As a result, differing treatment may be needed.
Ground-breaking results have come from a study conducted by Canadian researchers at the University of Pittsburgh and Centre for Addiction and Mental Health (CAMH), suggesting males and females may require different types of treatment for depression.
The post-mortem brain study found that males and females with MDD (major depressive disorder) have opposing changes in the expression of the same genes, making the results a world-first finding, since opposing pathology has not previously been reported.
Research has been undertaken for decades, so there are known differences in MDD between men and women (i.e., men are half as likely to be diagnosed with MDD, while women report a greater severity of illness as well as different types of symptoms to men). However, most of these studies that previously examined the brains of depressed subjects involved males only.
This study combined eight published datasets (four in men and four in women) in a meta-analysis and involved the examination of post-mortem brain tissue from 50 people with MDD (26 men and 24 women), compared to the same number of unaffected men and women.
Where females indicated an increased expression of genes affecting synapse function, males demonstrated a decreased expression of those same genes. When researchers applied their methods to data from a different set of subjects, the opposing changes were repeated.
When senior author Etienne Sibille, PhD, of CAMH, and her colleagues examined how much protein a gene produces, they found that typically, the genes that had changed expression occurred either in only females or only males. However, genes that were altered in both women and men did so in opposite directions. For example, where females indicated an increased expression of genes affecting synapse function (i.e., communication between neurons or between a neuron and a target cell like a gland or muscle), males demonstrated a decreased expression of those same genes. Similarly, females demonstrated decreases in genes affecting immune function, directly contrasting male results, which showed an increased expression of these genes. When researchers applied their methods to data from a different set of subjects, the opposing changes were repeated.
The study examined the three brain regions that regulate mood, which are dysfunctional in MDD: the amygdala, the dorsolateral prefrontal cortex and the anterior cingulate cortex. The opposite changes in gene expression were specific to these different regions. So if males showed an increased expression of a particular gene in one region and decreased in another, females demonstrated the exact opposite.
Lead author Marianne Seney, PhD, of University of Pittsburgh, said: “These results have significant implications for development of potential novel treatments, and suggest that these treatments should be developed separately for men and women.” For example, in their report, the authors suggest that new treatments targeting the sex-specific pathology in MDD may suppress immune function in men, or boost its function in women.