Reduced Activity in Key Brain Areas Seen in Women With Postpartum Depression, Pitt Study Finds

Certain brain areas of women with postpartum depression react less to images of scared or angry faces than those of women who are well, according to a study by University of Pittsburgh School of Medicine researchers that was published in a recent issue of the American Journal of Psychiatry. The researchers also found a reduction in brain activity that was associated with greater impairment of maternal attachment processes.

“The birth of a child is a greatly anticipated and desired life event, but it is paradoxically accompanied by maternal depression in 15 percent of new moms,” said Eydie L. Moses-Kolko, lead author of the study and an assistant professor of psychiatry at Pitt. “With our research, we are hoping to gain greater mechanistic understanding of postpartum depression, namely what is going on in the brains of depressed mothers.”

For the study, researchers compared 14 depressed and 16 healthy mothers, all of whom delivered a healthy term infant in the preceding 12 weeks, were medication-free, and had previously given birth to another child. Mothers were assessed using functional MRI to look at brain activity in relationship to prenatal depression, anxiety, and function, as well as with a questionnaire to determine attachment quality, hostility, and pleasure in interaction with their infants.

To fully engage the brain regions involved in emotion processing, the researchers used a well-known face-matching test: The mothers were shown images of angry and scared faces, and the researchers examined the mothers’ neural reactions to the images. Researchers found that negative emotional faces activated the left dorsomedial prefrontal cortex, which is a social cognition region of the brain, significantly less in depressed mothers than in healthy mothers. Deficits in this region, therefore, might represent diminished awareness of the emotions of others and less empathy for them. The researchers also found that while negative images were viewed, communication between the left dorsomedial prefrontal cortex and the left amygdala was present in healthy moms but not in depressed ones, suggesting that this might be an important neural circuit that regulates emotional responses to unpleasant stimuli, such as a crying baby.

“We also discovered that greater infant-related hostility and more severe depression were associated with reduced face-related amygdala activity, which may be a mechanism for the reduced attunement and empathic responses in some depressed moms that is described in the literature,” noted Moses-Kolko. “We need studies whereby brain responses can be directly related to live mother-infant behavior in order to definitely clarify brain mechanisms of mother-infant attachment. Ultimately, this information has the potential to guide the development of more effective treatments for postpartum depression.”

The study was supported in part by funding from the National Institute of Mental Health and the National Alliance for Research on Schizophrenia and Depression.