Have a Mood Disorder? Blame Your High-Strung Mom

More

A new study links a stress hormone in pregnant mothers to larger amygdalas in children, meaning potential headaches when it comes to emotional development.

2051224366_81f9730550-615.jpg
Flickr/Liz Henry

In previous research, we've learned that the size of the amygdala -- the part of the brain responsible for handling emotional response and threat perception -- can have an impact on our political outlook and the number of friends in our social networks. Now, a new study finds that maternal stress may be linked to amygdala volume in children, opening up new questions about how many of our social skills are shaped before we're even born.

In a paper published in the Proceedings of the National Academy of Sciences last month, researchers reported that mothers who experienced greater levels of stress during pregnancy tended to produce girls with larger amygdalas. After seven years, these offspring displayed more symptoms of affective disorders.

The scientists had mothers in the study undergo a saliva swab at 15 weeks of gestation to measure for stress hormones. Mothers who had more cortisol in their blood gave birth to girls whose right amygdalas were slightly larger, though the pattern didn't hold for boys. A one-standard deviation increase in maternal cortisol meant, on average, a 6.4 percent increase in amygdala size.

What's more, the girls who had larger amygdalas scored worse on the Child Behavior Checklist, a standard questionnaire designed to suss out behavioral problems in young people. "Susceptibility for affective disorders may, in part, be programmed in utero," the researchers concluded. "This effect may be mediated through changes in anatomy of the amygdala."

If the science is true, it offers another possible explanation for variations in brain physiology from person to person -- as well as why some people are more comfortable with uncertainty than others. It could also help explain why girls tend to experience mood disorders at greater rates than boys, a situation that until now was thought to be due to hormonal developments after birth or linked somehow to social expectations, said Victor Carrion, a Stanford professor in pediatric psychiatry.

"Even before you hit puberty, there may be things going on in the in-utero environment of girls that may render some girls more vulnerable to these affective symptoms," said Carrion in a phone interview. "So one possibility is that girls develop earlier -- as we know they do -- but that this translates very early in utero."

Update: Heidi Feldman, a Stanford professor of pediatrics in neonatal and developmental medicine, threw some cold water on the paper in a phone interview late Tuesday, saying the children at age 7 who'd been born to higher-stress mothers didn't appear to be much more emotionally challenged compared to those born to mothers under normal amounts of stress. Citing the study's own figures, Feldman pointed out that the difference between the two groups on a scale of affective symptoms was only a matter of two or three points.

"These girls are scoring very, very close to the the normal level," she said. "The mean for the girls is about 52 in this high cortisol group, compared to 50 for the control. None of these girls at age seven are extremely abnormal in their scores."

Feldman added that an abnormal score would be about ten points higher. While this doesn't necessarily invalidate the paper's findings, it's a good reminder that all research is a work in progress.

Jump to comments
Presented by

Brian Fung is the technology writer at National Journal. He was previously an associate editor at The Atlantic and has written for Foreign Policy and The Washington Post.

Get Today's Top Stories in Your Inbox (preview)

What Do You See When You Look in the Mirror?

In a series of candid video interviews, women talk about self-image, self-judgement, and what it means to love their bodies


Elsewhere on the web

Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register. blog comments powered by Disqus

Video

Adventures in Legal Weed

Colorado is now well into its first year as the first state to legalize recreational marijuana. How's it going? James Hamblin visits Aspen.

Video

What Makes a Story Great?

The storytellers behind House of CardsandThis American Life reflect on the creative process.

Video

Tracing Sriracha's Origin to Thailand

Ever wonder how the wildly popular hot sauce got its name? It all started in Si Racha.

Video

Where Confiscated Wildlife Ends Up

A government facility outside of Denver houses more than a million products of the illegal wildlife trade, from tigers and bears to bald eagles.

Video

Is Wine Healthy?

James Hamblin prepares to impress his date with knowledge about the health benefits of wine.

Video

The World's Largest Balloon Festival

Nine days, more than 700 balloons, and a whole lot of hot air

Writers

Up
Down

More in Health

Just In