UNIVERSITY PARK, Pa., May 3 (UPI) -- The timing of puberty in boys -- either earlier or later than peers -- can trigger chemicals linked to anti-social behavior, U.S. researchers suggest.
Elizabeth J. Susman, the Jean Phillips Shibley professor of biobehavioral health at Pennsylvania State University, and colleagues examined how puberty timing affects the stress hormone cortisol and salivary alpha amylase, an enzyme in saliva used as indicator of stress.
The study, published in the journal Psychoneuroendocrinology, found lower levels of alpha amylase in boys who experienced earlier maturity and higher levels of cortisol in boys who experienced later maturity. No similar correlation was found in girls, the study found.
"This is the first study to show that the timing of puberty moderates biological risks of ant-social behavior -- aggression, rule breaking, social and attention problems, defiance and conduct disorder," Susman said in a statement. "At puberty, boys produce a lot of testosterone and testosterone is a stress hormone as well, it may be that compared to girls, boys just have more biological hormone changes that may lead to anti-social behavior."
The researchers tested 135 boys and girls ages 8-13 for signs of anti-social behavior and collected saliva samples before and after a stressful laboratory test. Nurses determined the puberty stage of each child.