The research, published in Translational Psychiatry, shows that the proportion of adolescents who experience depression is higher than previous studies have reported; 36 percent for girls and 14 percent for boys. These depressive episodes are associated with poor outcomes - problems with school, relationships, suicide attempts - even with depression that started recently.
"Since we found that many more adolescents go through periods of depression than previously thought, it is important that we find ways to identify those individuals most likely to suffer the most severe consequences to make sure they are prioritized for treatment," said Joshua Breslau, Ph.D., Sc.D., researcher at the RAND Corporation and lead author of the study.
The researchers examined data from 2009 to 2014 collected annually from nationally representative samples of adolescents ages 12 to 17. They noted gender differences in the incidence of depression by age and compared recent first-onset and persistent depression with respect to impairment, suicide attempts, conduct problems and academic functioning.