A small study involving MRI brain scans suggested that women with postpartum depression have reduced activity in the parts of the brain that are responsible for controlling emotional responses and recognizing emotional cues in others.
“Our study provides a brain basis for what has been described in clinical settings and behavioral studies, which is that women with postpartum depression may have reduced activity in regions of the brain that process emotions and that are involved in being attuned to others’ emotions,” said study author Dr. Eydie L. Moses-Kolko, an assistant professor of psychiatry at the University of Pittsburgh School of Medicine. She added that this discovery may help explain why mothers with postpartum depression often have problems bonding with their infants.
Specifically, the study used a well-known face-matching test to engage regions of the brain involved in emotional processing in 14 depressed and 16 healthy mothers. All participants were free of medications and had previously given birth to another infant.
Neural reactions were examined as the mothers were shown images of angry and scared faces, and the results of the test revealed that the depressed women had less response when compared to mothers who were well.
Participants also filled out questionnaires providing insight into the quality of their attachment to their infant, the presence of hostility and pleasure interacting with their newborn.
Specifically, the study focused on how the negative images activated the left dorsomedial prefrontal cortex—the social cognition area of the brain. Mothers with postpartum depression had significantly less activation.
Researchers suggested that deficits in this region might contribute to a diminished awareness and empathy towards the emotions of others.
The study also revealed that communication between the left dorsomedial prefrontal cortex and the left amygdala was present in healthy moms but not in the depressed participants. This communication could be important in regulating and triggering emotional response to unpleasant sounds like a baby’s cry, researchers noted.
“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 Dr. 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.”
Statistics reveal that postpartum depression affects about 15 percent of new moms. While a greater percentage of new mothers are apt to feel what is defined as is “baby blues,” postpartum depression is different in that it may continue for months and become a debilitating factor to normal function.
The study was partly funded by the U.S. National Institute of Mental Health and the National Alliance for Research on Schizophrenia and Depression and can be found in the Sept. 15 online advance edition of the American Journal of Psychiatry.