Early puberty holds few long term dangers for girls

NEW YORK (Reuters Health) - Contrary to the conventional wisdom, most girls who start developing a year or two before their classmates don't face any more long-term problems than their peers, according to a new study.

However, depression may be somewhat more likely among such girls, Duke University researchers report this month in the American Journal of Psychiatry.

"This is a hopeful study," co-author William Copeland told Reuters Health.

Two decades of research suggests early-maturing girls are more likely to engage in numerous high-risk behaviors such as sexual activity, substance abuse, minor criminal activity, and clashes with authority figures. It was thought that this behavior persisted into young adulthood.

The Duke study, however, is the first study to follow a large group of girls until the age of 21.

The Copeland group used data from the Great Smoky Mountain Study, a long-term study of more than a thousand city and rural boys and girls in North Carolina. The girls enrolled in the study were followed from age 9 to 21. Of the 630 girls enrolled, 115, or about one in five, were defined as early-maturers.

Based on regular surveys of the subjects and their parents, while the research reinforced the belief that early-maturing girls have more problems in adolescence, it also found "little evidence of continued problems into young adulthood."

In fact, the discrepancies between the early and on-time maturing girls disappeared for two reasons: early-maturers gradually reduced risky behaviors, while their on-time peers increased theirs.

Depression in young adulthood was the only exception and showed a stubborn persistence in one small group of early-maturers.

Compared to all study participants, early-maturers were 3 times more likely to be depressed as young adults: Fifteen percent of early-maturers suffered depression in young adulthood, compared to five percent of girls who matured on time or late.

The effect was particularly pronounced in a small group of early-maturers. More than 80 percent of the early-maturing girls reporting a history of behavior problems were depressed at 21, compared to nine percent of those without histories of misbehavior.

The finding offers opportunities for helping these girls, Copeland said. "We can identify them early through their behaviors and target them for intervention," he said.

This study, Copeland said, offered "good news all around." Although as a whole, the early-maturers showed a higher rate of depression, "most of these girls are doing just fine."

SOURCE: here American Journal of Psychiatry, published first online May 17, 2010.