14 DAY TRIAL // Women with the baby blues process negative emotions differently than new mothers without the condition, says a team of scientists led by Mary Phillips at the University of Pittsburgh, Pennsylvania.
Postpartum depression is a very serious health problem, that occurs to 15% of new mothers and can have significant consequences for them, as well as for their children and families.
The neural processes involved in postpartum depression are not entirely known, but the way that the brain processes emotions seems to occur in other affective disorders as well.
So Mary Phillips and colleagues, used functional magnetic resonance imaging on the brains of 14 unmedicated women with post-natal depression and 16 completely healthy ones, while they were looking at images of sad and angry faces.
The scientists looked for reactions in the dorsomedial pre-frontal cortex and amygdala, as these are the emotion regulatory neural regions of importance to both mothering and depression.
They concluded that depressed women, unlike healthy mothers, had significantly reduced left dorsomedial prefrontal cortical face-related activity - they dorsomedial prefrontal cortex being the area of the brain thought to pick up on emotional cues and mediate emotional responses.
In depressed mothers, researchers also noticed that there was a high negative correlation between left amygdala activity and postpartum depression severity and a significant positive link between right amygdala activity and absence of infant-related hostility.
Women suffering from post-natal depression have difficulties bonding with their babies, but Phillips suggests that this might be linked to a more general loss of interest in social interactions.
Scientists had previously found that people with depression are more sensitive to negative images than healthy people, but this study says that new mothers with post-natal depression counter theory because they eliminate negativity and do not react to it.
Phillips does not think that this phenomenon is caused by pregnancy alone because this reaction of the brain did not appear to healthy new mothers.
On this study, Mary L. Phillips, M.D worked with Eydie L. Moses-Kolko, M.D., Susan B. Perlman, Ph.D., Katherine L. Wisner, M.D., M.S., Jeffrey James, B.S., and A. Tova Saul, B.A., from the Department of Psychiatry, Western Psychiatric Institute and Clinic - University of Pittsburgh Medical Center, Pittsburgh, the Departments of Obstetrics and Gynecology and Reproductive Sciences and Radiology - University of Pittsburgh Medical Center, the Departments of Epidemiology and Women's Studies - University of Pittsburgh and the Department of Psychological Medicine - Cardiff University School of Medicine, Cardiff, United Kingdom.
The study was published in the American Journal of Psychiatry.