More and more teenage girls are falling into the depression trap and this may be the result of girls' greater exposure to stressful interpersonal events, making them more likely to ruminate.
"Our findings draw our focus to the important role of stress as a potential causal factor in the development of vulnerabilities to depression, particularly among girls," said psychology researcher Jessica Hamilton from the Temple University, Philadelphia in the US.
Teenagers who tend to interpret events in negative ways and who tend to focus on their thoughts following such events (rumination) are at greater risk of depression.
Hamilton hypothesised that life stressors like fight with a family member or friend would ultimately increase a teenager's risk of depression.
To reach the conclusion, researchers examined data from 382 adolescents participating in an ongoing longitudinal study.
The adolescents completed self-report measures evaluating cognitive vulnerabilities and depressive symptoms at an initial assessment, and then completed three follow-up assessments, each spaced about seven months apart.
As expected, girls tended to show more depressive symptoms at follow-up assessments than did boys.
Girls also were exposed to a greater number of interpersonal dependent stressors during that time.
"It is the exposure to stressors that maintained girls' higher levels of rumination and, thus, their risk for depression over time," researchers found.
"Simply put, if boys and girls had been exposed to the same number of stressors, both would have been likely to develop rumination and negative cognitive styles," Hamilton explained.
"Parents, educators and clinicians should understand that girls' greater exposure to interpersonal stressors places them at risk for vulnerability to depression and ultimately, depression itself," Hamilton noted.
The findings were detailed in the journal Clinical Psychological Science.