A study published Sunday in the journal Nature Neuroscience suggests that baby girls living with stressed-out moms may be more stressed themselves as young children and more prone to anxiety as adolescents than those born into more serene families.
Researchers at the University of Wisconsin-Madison used a form of MRI that scans the brain during its resting state to map stress-related brain activity in 57 18-year-olds (28 female, 29 male) who had been long-term participants in the Wisconsin Study of Families and Work (WSFW). The WSFW study was launched in 1990 and 1991 to examine sources of stress among families with young children; 570 children and their families were initially enrolled, and many participants who were infants back then continue to take part today, according to news materials.
The MRI scans were aimed at determining how strong a connection existed between the amygdala, a part of the brain that responds to negative emotion and threat, and the prefrontal cortex, which helps process and regulate negative emotion, the study explains.
When researchers checked information about those participants that had been gathered at earlier points through the WSFW, they found that girls in whom the connection between those two key brain areas was weak had as infants lived with mothers who had reported high stress levels (related to depression, the general frustrations of parenthood or feeling overwhelmed by that experience and financial or marital problems).
Those girls were also on record as having had elevated levels of the stress hormone cortisol (as measured by saliva test at the end of the day) when they were four-year-olds. High cortisol levels late in the day are considered a marker of stress a child has undergone during the day, the study notes.
Close to the time that the adolescents’ brains were scanned, the subjects were tested for current levels of stress, anxiety and depression. No link between their current stress levels and the strength of the amygdala/prefrontal cortex connection was found, but females with weak connections had more current symptoms of anxiety (but not of depression).
All of that evidence suggests, the authors explain, that the brains of baby girls living in stressed households may be shaped by that experience, as high levels of cortisol weakened the connection between those two mood-governing areas of the brain, and that that early experience may have a lasting influence.
No such chain of events was evident among male participants. While that phenomenon warrants further study, the authors note, it points to a potential benefit for early-life interventions for baby girls living in stress-filled households.