Early-maturing girls could be more impressionable

Girls who start puberty early may be at particular risk for problem behaviors as teenagers, a new study suggests.

But parents who are alert to the risk might be able to step in and prevent the problems, the researchers say.

The risk might be related to the girls' friendships. In their study, girls whose bodies started to change before age 11 were more likely later on to have best friends who misbehave.

But, the researchers found, most of these harmful friendships weren't yet formed by age 11. So while the girls are still young, this might be a time for parents to monitor them closely, support them, and prevent these dangerous friendships from getting started.

"Peers are increasingly influential from childhood through adolescence, and girls who mature earlier than their peers may be drawn to more delinquent friends for a variety of reasons, such as wanting to fit in, being teased by other classmates, or not having the emotional development or social competence to match their advanced physical development," Erika Westling told Reuters Health.

Westling researches personality and health at the Oregon Research Institute in Eugene but was not involved in the new study.

"As this research shows, early maturers appear to be more vulnerable to peer influences than non-early maturers, so they may not be able to resist peer pressure as effectively," Westling added.

Sylvie Mrug, a psychologist at the University of Alabama at Birmingham, and her colleagues interviewed 2,600 girls at age 11, 13 and 16 years old, and their parents. The girls reported on their own behavior issues, those of their best friend, and any incidences of physical or nonphysical aggression.

Out of every 100 girls in the study, 16 had "matured early," that is, they got their periods for the first time before age 11. (The average age for first period to occur is 12.)

As expected, girls whose best friends had behavior problems were very likely to have similar behavior problems themselves.

And girls who entered puberty early had a stronger link between best friend's problems and their own problems, which suggests more vulnerability to peer influences, the authors write in Pediatrics.

Mrug and her colleagues accounted for parental education, household income, family structure and ethnicity. They were not able, however, to account for parental conflict or parenting behaviors, which might also be important in determining girls' behavior, Mrug said.

"For girls, early puberty is associated with more emotional problems, such as depressive symptoms and lower self-esteem, as well as more problem behaviors, such as delinquency, aggression, substance use, and risky sexual behavior," Mrug said. "For boys the results are less consistent, but early puberty has also been linked with more problem behaviors."