The number of teens reporting depression is on the rise according to new US research, and is growing at an even faster rate among teenage girls.
According to the study, reports of depression increased by 37 percent over the decade ending in 2014, with one in six adolescent girls reporting an episode in the past year.
Led by the Johns Hopkins Bloomberg School of Public Health, the team of researchers analyzed data from the 2005 to 2014 National Surveys on Drug Use and Health on adolescents and young adults to look at trends in "major depressive episodes" over the previous year.
Also known as clinical depression, major depressive episodes occur when someone develops a depressed mood or a loss of interest or pleasure in everyday activities, along with other depressive symptoms, consistently for at least two weeks.
In total 176,245 adolescents aged 12 to 17 and 180,459 adults aged 18 to 25 were involved in the annual study between 2005 and 2014.
Participants were told what the symptoms of depression were, and asked to report on whether they had experienced any of them in the previous year.
The reports revealed that in 2005, 8.7 percent of teens had experienced a major depressive episode in the past year, with this figure rising to 11.3 percent in 2014.
Among teen girls this figure was even higher, rising from 13.1 percent in 2005 to 17.3 percent in 2014.
The team also observed that whites were more likely than non-whites to experience these episodes, with the rates increasing from 8.8 percent in 2005 to 9.6 percent in 2015, although the increase was only found in those age 18 to 20.
The study found no increase in depression rates among 21 to 25-year olds.
Although the findings were based only on self-reports not on clinical diagnoses, which can be subject to error, the results are still worrying, with lead researcher Ramin Mojtabai commenting that, "This shows us there are a growing number of untreated adolescents with depression and that we are making few inroads in getting mental health care to this population. It is imperative that we find ways to reach these teenagers and help them manage their depression."
Although the team are unsure about what is causing the increase, especially among young girls, they suggest mobile phone use could be partly to blame. Problematic mobile phone use among young people has already been linked to depressed mood and cyberbullying via mobile phones may have also increased in recent years, particularly among girls who use their mobile phones more frequently and intensively than boys.
The findings can be found published online the journal Pediatrics.