Researchers know there’s a genetic connection with postpartum depression (PPD), but a new investigation—the largest-ever analysis of genetic studies on PPD—tells us even more about its genetic origins.
The report was published on Oct. 18 in the American Journal of Psychiatry.
Jerry Guintivano, PhD, an assistant professor of psychiatry at the UNC School of Medicine, said the study showed that the genetic architecture of PPD is similar to that of the genetic architecture of major depression, posttraumatic stress disorder, bipolar disorder, anxiety disorders, insomnia, and polycystic ovary syndrome. Translation: PPD may happen because the genes involved in the other conditions are already at work.
“We studied about 1.1 million regions of the human genome,” Dr. Guintivano said, “and we can see that PPD has a similar genetic signature to these other psychiatric conditions.”
GABA, the neurotransmitter that plays a role in brain communication and produces a calming effect, is involved in the puzzle. Areas of the brain (the thalamus and hypothalamus) involving GABAergic neurons that release GABA are tied to PPD, too. Both Brexanolone and zuranolone, the only two treatments for PPD approved by the US Food and Drug Administration (FDA), also act on the GABAergic neurons, the researchers say.
“We view our finding as a refinement of the mechanism by which brexanolone works,” Dr. Guintivano said. “We now have preliminary evidence suggesting we should target GABAergic neurons in the thalamus and hypothalamus for future research.”
The researchers used multiple cohorts from people across the globe. In all, the scientists assessed 18,770 people with PPD and compared it to 58,461 people who didn’t have the postpartum mental health condition.
The study and the amount of data included sounds massive, but there are still too few cases to pinpoint specific locations within the genome that are associated with PPD risk, the authors said.