There is a growing trend in young adults that treatments are not keeping up.
For youth ages 12 to 17, the prevalence of depression increased from 8.7 percent in 2005 to 11.3 percent in 2014, the study found. Among adults aged 18 to 25, the prevalence climbed from 8.8 percent to 9.6 percent during the study period.
This study examined national trends in 12-month prevalence of major depressive episodes (MDEs) in adolescents and young adults overall and in different sociodemographic groups, as well as trends in depression treatment between 2005 and 2014.
"We already know that teens have much more depression than is currently being recognized or treated," said Dr. Anne Glowinski, a child psychiatry researcher at Washington University in St. Louis who wrote an editorial accompanying the study.
Each year, about one in 11 teens and young adults suffers at least one episode of major depression, researchers report in Pediatrics, online November 14.
To examine trends over time in the prevalence of depression and mental health treatment, researchers examined nationally representative survey data from more than 172,000 teens and almost 179,000 young adults.
Among other things, researchers asked participants if they had experienced a variety of symptoms that can point to depression, whether they had experienced an episode of major depression in the past year, and if they had seen a doctor or other health professional about these symptoms.
They also assessed whether the participants received treatments such as counseling or prescription medication.
Compared to teens who didn't report a major depressive episode, those who did were more likely to be older, not in school, unemployed, in households with single parents or no parents, and have substance abuse issues.
One limitation of the study is that researchers relied on young people to accurately recall and report any symptoms of depression or treatments for the condition, the authors note. The study didn't include medical records and researchers couldn't verify whether clinicians diagnosed depression in individual participants who reported symptoms or said they received treatment.
"Many children do not tell their parents about their depressive symptoms, they may not even recognize them as such," said lead study author Dr. Ramin Mojtabai, a public health researcher at Johns Hopkins University in Baltimore.
Conclusion: The prevalence of depression in adolescents and young adults has increased in recent years. In the context of little change in mental health treatments, trends in prevalence translate into a growing number of young people with untreated depression.