Teenage girls are more likely to struggle with anxiety and depression if they're exposed to stress as babies, a study has found.

Those who spent their first year being raised by mothers with depression, relationship troubles or financial woes tended to have higher levels of stress hormone, cortisol, in their blood as toddlers.

By the time they were in their teens, there were also marked differences in their brain development from other girls. Two areas of the brain which regulate emotions were affected. This correlated with them experiencing anxiety and symptoms of depression at the age of 18.

Researchers believe the study shows how stress early in life can lead to the development of mood disorders. They believe it could one day be used to decide whether intervention is needed when a child is young.


"We wanted to understand how stress early in life impacts patterns of brain development which might lead to anxiety and depression," said author Dr Cory Burghy of the Waisman Laboratory for Brain Imaging and Behaviour at the University of Wisconsin, Madison.

"Young girls who, as pre-schoolers, had heightened cortisol levels, go on to show lower brain connectivity in important neural pathways for emotion regulation - and that predicts symptoms of anxiety during adolescence."

In contrast, young men were unaffected in later years by family stress in their early life, according to the research.

For the study, published in the journal Nature Neuroscience, Dr Burghy looked at 57 children - 28 female and 29 male - who had been part of long-running research by the university.

They found that girls with raised cortisol by the time they were four-years-old also had weaker brain connections. Scientists then discovered they had lived in homes where their mothers had reported higher general levels of stress, which could include symptoms of depression.

Dr Richard Davidson, a professor of psychology and psychiatry who works alongside Dr Burghy, said: "Our findings raise questions on how boys and girls differ in the life impact of early stress.

"We do know that women report higher levels of mood and anxiety disorders, and these sex-based differences are very pronounced, especially in adolescence."