Is This Why More Women Than Men Have Anxiety? New Study Digs In
Unfair as it may be, it's simply a fact that women suffer from anxiety more often than men. In fact, according to the Anxiety and Depression Association of America, from the time they reach puberty until the age of 50, women are two times more likely to have an anxiety disorder than their male counterparts.
The roots of anxiety and other mental health disorders, like OCD and depression, are hard to pin down. But a new study, published in Cell Reports, gets us one step closer to understanding the underlying causes of anxiety—and why women are particularly at risk.
The research was conducted by scientists at the University of Utah who were able to make a few important discoveries. First, they found a new lineage of specialized brain cells. Second, they uncovered that a dysfunction in these brain cells, which are called Hoxb8-lineage microglia, can be linked to anxiety-like behaviors and stress response. And finally, they found that this relationship is exacerbated by female sex hormones. As the authors of the study wrote: "We show that the severity of the pathology is set by female sex hormones."
Microglia are cells that play a critical role in the development of brain structures and neural circuitry while we're in the womb. And while we've long known that there are at least two sublineages of these cells—and that the Hoxb8-lineage represents about 30% of the total microglia in the brain—we didn't know what they actually did, and we certainly didn't know they played such a positive role in mental health.
This is the first study to show that these cells play a role in anxiety behaviors in mice. As lead author Dimitri Traenkner explained, "Researchers have long suspected that microglia have a role in anxiety and neuropsychological disorders in humans because this cell type can release substances that may harm neurons. So, we were surprised to find that microglia actually protect from anxiety, they don't cause it."
To establish a connection between this relationship and sex hormones, the researchers manipulated the estrogen and progesterone levels in the mice and observed their behavior. They found that the female mice exhibited much more severe signs of anxiety, and when men were given hormones to mimic those in a female, the male's anxiety would shoot up in response. "Our findings strongly argue for a mechanistic link between biological sex and genetic family history in the risk to develop anxiety disorders," said Traenkner.
So what does this mean for the 19% of U.S. adults living with an anxiety disorder? Traenkner explains that "it opens up a new avenue for thinking about anxiety. Since we have this model, we have a way to test new drugs to help these mice and hopefully at some point, this will help people." In the future, we may be able to target the root causes of anxiety more efficiently using a combination of knowledge about female hormones and this new sublineage of brain cells. "More women than men experience debilitating anxiety at some point in their lives. Scientists want help these people to get their lives back," he continued.
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