According to the results of a new scientific study published in the journal Biological Psychiatry,  women with alcohol use disorder (AUD) have lower levels of brain immune cells called microglia compared to women who do not have AUD. Moreover, the findings of the study, carried out by researchers at Yale University, show that this is not the case for men.

In recent years, AUD has been on the rise in women, and research shows that women who consume excessive levels of alcohol are at an increased risk for brain damage, cognitive deficits, and a range of other adverse effects compared to men.

Moreover, the authors of the study suggest that in women, excessive alcohol consumption may lead to chronic activation of microglia, potentially “exhausting” these immune cells and reducing their effectiveness. In turn, the reduced neuroimmune response could help explain why women are particularly susceptible to the harmful effects of alcohol on the brain.

“A couple of drinks will wake up the microglia to see if there’s a problem,” says Dr. Kelly Cosgrove, professor of psychiatry at Yale School of Medicine and senior author of the study, in her interview with Medical Xpress. “But if you do that every day over years, or over decades, they eventually give up. And then you can start to see cognitive decline.”

The study included both men and women diagnosed with mild to moderate AUD, along with healthy control participants. All individuals underwent positron emission tomography (PET) scans to examine microglia activity in the brain, completed mood and anxiety questionnaires, and participated in cognitive function testing.

The study results demonstrate that healthy women have higher levels of microglia compared to healthy men. “The healthy brains of women have higher levels of microglia, and that may or may not go along with the fact that women do have an increased propensity to immune-related disorders,” said Dr. Cosgrove.

Among individuals with AUD, there was a microglial deficit in women compared to their healthy counterparts, but not in men. Furthermore, women with AUD also had lower levels of executive functioning, which involves using cognitive skills we use to complete everyday tasks such as planning or problem solving.

“This is a glimmer into how immune system dysfunction is associated with cognitive function,” Cosgrove said. “If you don’t have a healthy brain immune system, then other parts downstream will start to break down as well.”

Currently, most available treatments for AUD  were developed based on research involving primarily men. The results of this new study could help inform the development of novel therapeutics designed for women that target the brain’s immune system.