When puberty arrives earlier or later relative to their peers, adolescent boys may suffer a chemical imbalance linked to antisocial behavior, say Penn State University researchers. Their study appears in the journal Psychoneuroendocrinology.
For the study, researcher Elizabeth J. Susman looked at how the timing of puberty affects cortisol, a stress hormone, and salivary alpha amylase, an enzyme in saliva used as indicator of stress. She found that lower levels of the alpha amylase in boys who experienced earlier maturity and higher levels of cortisol in boys who experienced later maturity are related to antisocial behavior. There was no similar correlation in girls.
"This is the first study to show that the timing of puberty moderates biological risks of antisocial behavior," said Susman. "Parents should be especially sensitive to picking up signs of earlier or later puberty in their children. Puberty can be stressful - behaviorally and biologically - on the kids."
The researchers used a child behavior checklist to test 135 boys and girls aged between 8 and 13 for signs of antisocial behavior. They also collected saliva samples before and after a stressful laboratory test, while pediatric nurses determined the stage of puberty for each child. Analysis of the children's cortisol and salivary enzyme levels, as well as the timing of puberty and symptoms of antisocial behavior, suggest that overall, antisocial boys are characterized by a later onset of puberty and higher levels of cortisol.
However, boys who reached puberty earlier and had lower levels of the salivary enzyme specifically showed greater problems related to rule breaking and conduct disorder. These boys were also more aggressive than those in the group that experienced puberty later.
Why the findings only relate to boys and not girls remains unclear. "At puberty, boys produce a lot of testosterone and testosterone is a stress hormone as well," added Susman. "It may be that compared to girls, boys just have more biological hormone changes that may lead to antisocial behavior."
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Source: Penn State University