Hyperactive young girls are more likely to have "serious" problems in adulthood, research suggests.
A study of more than 800 girls up to the age of 21 found that hyperactivity was linked to poor job prospects, abusive relationships and teenage pregnancy.
Previous research on the lasting impact of childhood hyperactivity has focused on boys, who are more likely to be diagnosed and treated.
The Canadian and UK study is reported in the Archives of General Psychiatry.
Young girls with high levels of hyperactivity should be targeted early in life to help them achieve better at school, the researchers concluded.
The study, which assessed girls yearly between the age of six and 12, looked for signs of restlessness, jumping up and down, not keeping still, and being fidgety.
Researchers also assessed physical aggression such as fighting, bullying, kicking, biting or hitting.
One in 10 showed high levels of hyperactive behaviour, while another one in 10 showed both high levels of hyperactive and physically aggressive behaviour.
Those who were the most hyperactive or aggressive were more than twice as likely to be addicted to smoking, fall into mentally abusive relationships and four times more likely to do poorly at school.
However, only girls with both hyperactivity and physical aggression were found to report later problems of physical as well as psychological aggression towards their partner, along with early pregnancy and dependency on welfare.
A quarter of girls with hyperactivity had no problems in adulthood.
Study leader, Dr Nathalie Fontaine, a researcher at University College of London, said there had been very little research on hyperactivity in girls.
"Hyperactivity is less common in girls than in boys but there are girls with this behaviour which can lead to serious problems in later life."
She said the findings were not unexpected as many of the problems stemmed from poorer achievement at school.
"We need more research to understand the factors that prevent or trigger the development of such problems.
"There are very few interventions targeting females so we don't know exactly what to do and that needs to be looked at in more detail."
Dr Morris Zwi, consultant in child and adolescent psychiatry at South West London and St Georges Mental Health Trust, said similar outcomes had been shown in hyperactive boys.
"Hyperactivity is diagnosed more commonly in boys and we don't know the reason for that.
"Girls tend to be more inattentive so they're just left to get on with things because they're not causing so much trouble."
He said schools did not have the skills to deal with children with hyperactivity problems but there were programmes which could help
children, including psychological therapies.
"The key thing is having someone who understands but also just a sensitive human being who can have a conversation with a young person."