Study Links Early Puberty in Girls to Delinquent and Physically Aggressive Behavior

A study by researchers at the University of Alabama at Birmingham says that adolescent girls who mature at an early age, before 11 years, are more likely to display delinquent and aggressive behavior.

"Delinquency and aggression put adolescents at risk for many negative outcomes in the future, including lower educational achievement, substance abuse, depression and problems in relationships," the study's lead author Sylvie Mrug, Ph.D., associate professor in the UAB Department of Psychology, said in a statement. "Thus it is important to understand how these problem behaviors develop and how pubertal timing and friends' behavior -- among other variables -- contribute to them."

Early puberty in girls can lead to several physical and emotional problems. A study conducted in the past that was published in the Pediatrics journal linked early puberty in girls to obesity. Other problems triggered due to early onset of puberty are short stature, early sexual activity, stressful life, behavior problems and also a slightly increased risk of breast cancer in later life.

Adding to the volume of evidence available on problems linked with early puberty, the current study states that by the age of 16, physical aggression due to early onset of puberty gradually disappears but delinquent behavior persists.

For the study, researchers interviewed 2,600 girls and their parents on three different occasions between the ages of 11-16. The researchers wanted to ascertain if early puberty and best friend's problem behavior contributed to delinquency and aggression in these girls.

It was seen that girls who had  best friends with  problematic behavior such as lying, cheating, not being good, talking back to adults, showed a more delinquent as well as aggressive behavior at the age of 11. But this behavior disappeared by the age of 16 in most girls. This indicates that a maturing teen is more susceptible to negative peer influence.

Mrug said, "This suggests that negative peer influences from best friends at age 11 are short-lived, perhaps because best friends change as children enter middle school. The most interesting finding was that girls who experienced early puberty reported more delinquent behavior if their best friend was more deviant. It is important for parents and other adults to monitor who the friends are and what the girls do with their friends. Of course this is important for all children and adolescents, but it may be even more critical for girls who mature early, as they are more vulnerable."

The researchers also identified that early onset of puberty and behavior problems of best friend at  age 11 do not trigger long term behavior problems.

The finding was published in the journal Pediatrics.