Teen Aggression May Really Be a Sta...( Study finds biological differences in...),Health

Study finds biological differences in brains of combative kids

TUESDAY, Feb. 26 (HealthDay News) -- For parents of emotionally combative teens, new research offers a powerful biological reason for all the family feuding -- adolescent brain size.

A team of Australian scientists has found that when key regions of the brain known for controlling emotions are bigger, boys and girls tend to be more aggressive and more persistent during their fights with Mom and Dad.

"This is a bit of a unique study," said study author Nicholas Allen, an associate professor with the Orygen Research Centre at the University of Melbourne. "Because we've shown for the first time that in terms of aggression -- not physical, but being argumentative and unfriendly -- some of the differences in the way teen kids interact with parents are biologically based. The adolescent is developing, their brain is developing, and there's a link between the two."

The finding was published in this week's online issue of the Proceedings of the National Academy of Sciences.

The authors first videotaped 20-minute "problem-solving" discussions with 137 Australian teens between the ages of 11 and 14 and one of their parents. The interactions were spurred on by the introduction of provocative family issues, and analyzed for language and emotional content.

Following MRI scans of the teens' brains, Allen and his colleagues observed that children with large amygdala regions were more likely to engage in longer and more aggressive arguments with their parents.

They also reported that male -- but not female -- teens possessing an atypical unevenness in the size of two left brain regions -- the anterior cingulate cortex and the orbitofrontal cortex -- were also more likely to maintain aggressive behavior, as well as whiny and anxiety-laced behavior (collectively referred to as dysphoria).

In an attempt to explain gender vari
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