Women who start their period earlier than their peers are more likely to experience depression well into their late 20s, new research claims.
Researchers said this may be due to a mismatch between how girls look and cognitive and emotional maturity.
The average age girls start menstruating is 12, but researchers say one-third American girls are now entering puberty by the age of eight.
Previous studies have linked early maturing in young girls to psychological vulnerability in their teen years, but this is the new study led by Cornell University reveals that the impacts may last far longer than previously thought.
Researchers found women who start menstruating at a younger age are psychologically vulnerable well into adulthood
Dr Jane Mendle, associate professor at Cornell University, said the findings reveal that puberty has long-term effects.
‘Early maturers may look old, but they still think and feel like other girls their age,’ Dr Mendle told Daily Mail Online.
‘This mismatch can sometimes make it more difficult to adapt to all of the new changes and experiences that accompany this transition,’ she added.
Depression is common mental health disorder that is most common in women in their late 20s and early 30s, according to the Anxiety and Depression Association of America.
For the study, Dr Mendle and her colleagues tracked 7,800 girls for 14 years, from adolescence to their late 20s, using data from the National Longitudinal Study of Adolescent Health.
The subjects were between 11 and 21 years old when researchers started tracking them and were asked about when they began menstruating and about any symptoms of depression and antisocial behavior they had experienced throughout their lives.
The researchers also asked the girls and women about other factors associated with early puberty and mental health problems, such as household income and whether their father was absent.
Researchers found women who experienced early puberty had higher rates of depressive symptoms.
They found early-maturers also showed signs of antisocial behavior, with many of they reporting more rule-breaking and delinquency. Their behavior got worse as they aged, which is the exact opposite pattern normally developing teens displayed.
‘Usually people aren’t shoplifting at 25 as much as they do at 15,’ Dr Mendle said. ‘But these kids did not show the typical age-related declines in antisocial behavior, and their behaviors got worse.’
She said there’s no single reason why early puberty is associated with increased vulnerability.
‘Many different biological and social factors combine together,’ Dr Mendle said, about girls who got through puberty are more likely to develop mental health problems.
‘But a big issue is the mismatch between physical, cognitive, and emotional development. As girls enter puberty, they start to look older – and the world often responds to that,’ she added.
Previous studies have linked early puberty in girls to an increase risk of mental health problems like depression during the teen years.
A 2014 study published in the Journal of Affective Disorders found girls who get their first period earlier are more likely to experience depression.
However, researchers aren’t sure why the psychological effects of puberty last into the late 20s.
Dr Lauren Streicher, medical director of the Center for Sexual Health and the Center for Menopause, said this may due to difficulties that started in adolescence.
‘Someone who is a depressed teen is more likely to be a depressed adult,’ said Dr Streicher who was not involved in the study.
The age at which most girls get their periods has become younger and younger over the past 50 years.
Dr Mendle said the lack of understanding about the long-term effects of early puberty is a public health issue, and pediatricians must be aware of how long these psychological problems can last.