High levels of family stress during infancy are associated with future anxiety and everyday brain function problems in teen girls, according to a new study at the University of Wisconsin-Madison.
Babies who lived with stressed mothers were more likely to become preschoolers with higher levels of cortisol, a stress hormone. Fourteen years later, these girls with higher cortisol showed weaker communication between brain areas associated with emotion regulation.
Finally, both high cortisol and differences in brain activity predicted higher levels of anxiety at age 18.
The males in the study did not show any of these patterns.
“We wanted to understand how stress early in life impacts patterns of brain development which might lead to anxiety and depression,” said Dr. Cory Burghy of the Waisman Laboratory for Brain Imaging and Behavior.
“Young girls who, as preschoolers, had heightened cortisol levels, go on to show lower brain connectivity in important neural pathways for emotion regulation — and that predicts symptoms of anxiety during adolescence,” said Burghy.
For the study, scans designed by Dr. Rasmus Birn, assistant professor of psychiatry, showed that teen girls whose mothers reported high levels of family stress when the girls were babies had weaker connections between the amygdala (threat center of the brain) and the ventromedial prefrontal cortex (responsible for emotional regulation).
Birn used resting-state functional connectivity (fcMRI), a method which looks at the brain connections while the brain is at a resting state.
“This will pave the way to better understanding of how the brain develops, and could give us insight into ways to intervene when children are young,” said Richard Davidson, Ph.D., professor of psychology and psychiatry at UW.
The brains of 57 participants (28 females and 29 males) were scanned to reveal the strength of connections between the amygdale — a brain region known for its sensitivity to negative emotion and threat — and the prefrontal cortex, which is associated with helping to process and regulate negative emotion.
The researchers then looked back at earlier results and found that girls with weaker connections had, as infants, lived with mothers who had reported higher overall levels of stress. This includes symptoms of depression, parenting frustration, marital conflict, feeling overwhelmed in their role as a parent, and/or financial stress.
At the age of four, these girls also showed higher levels of cortisol late in the day, which is considered a measure of stress experienced during the day.
Near the time of the scan, the teenagers reported their anxiety symptoms and the amount of stress experienced in their lives. The researchers found a connection with childhood stress, rather than current stress levels. This suggests that higher cortisol levels in childhood could have affected the girls’ developing brains, resulting in lower connections between the prefrontal cortex and amygdala.
“Our findings raise questions on how boys and girls differ in the life impact of early stress,” said Davidson, director of the Lab for Affective Neuroscience at UW.” We do know that women report higher levels of mood and anxiety disorders, and these sex-based differences are very pronounced, especially in adolescence.”
Source: University of Wisconsin-Madison