(RxWiki News) Anxiety tends to be more common among women than men, according to various studies. But researchers don't know why. Now they're learning that it may have to do with baby girls' environment.
A recent study found a link between family stress when girls were babies and girls' anxiety levels as teenagers.
Girls who grew up in stressful homes were more anxious as teens. They also had weaker connections in a part of the brain related to dealing with negative emotion.
"Reduce stressful influences on kids."
The study, led by Cory A. Burghy, PhD, a post-doctoral researcher at the Waisman Laboratory for Brain Imaging and Behavior at the University of Wisconsin-Madison, pulled data from a long-term study that initially involved 570 children and their families, starting in 1990 and 1991.
The original study focused on how family stress was affected by maternity leave, day care and other factors.
This current study's findings came from brain scans of 57 of the now-grown children when they were 18 years old, using a technique called resting-state functional connectivity magnetic resonance imaging (fcMRI).
The teens were also asked at the time of the brain scans about their current stress and anxiety levels.
In the 28 females and 29 males who participated, researchers investigated the connections between two main areas of their brains: the amygdala and the prefrontal cortex.
The amygdala is related to a person's sensitivity for threats and other negative emotions. The prefrontal cortex is the brain's processing center which processes and regulates all emotions.
The researchers found that the females who had weaker connections between the amygdala and the prefrontal cortex had lived with mothers who reported higher stress levels when the girls were babies.
The mothers may have reported depression, frustration with parenting, conflict with a partner, feelings of being overwhelmed or financial strain.
Because the children were tracked through childhood and adolescence, the researchers were able to look at cortisol levels in the kids with saliva samples taken when they were 4 years old.
The girls with the weaker amygdala-prefrontal cortex brain connection and the more stressed moms also had higher levels of cortisol in their saliva (as 4-year-olds) late in the day.
Cortisol is a hormone that indicates a person's stress levels, so these girls appears to have felt more stressed during the day.
These girls also reported higher levels of anxiety as teenagers. However, the link between the weaker connections in the brain scans and anxiety was strongest for childhood stress, not current levels of stress.
In other words, the researchers were able to determine that for the girls only, childhood stress appeared to weaken the brain's ability to deal with the stress as effectively, and these girls were more anxious teens.
"Our findings raise questions on how boys and girls differ in the life impact of early stress,'' said co-author Richard Davidson, PhD in a release about the study. "We do know that women report higher levels of mood and anxiety disorders, and these sex-based differences are very pronounced, especially in adolescence."
Dr. Davidson is a professor of psychology and psychiatry at the UW Waisman Lab. "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," Dr. Davidson added.
The study was published November 11 in the journal Nature Neuroscience. The research was funded by the National Institutes of Health, the John D. and Catherine T. MacArthur Foundation Research Network on Psychopathology and Development and the HealthEmotions Research Institute at the University of Wisconsin School of Medicine and Public Health. The authors declared no conflicts of interest.