Researchers have identified the first biomarker for identifying those adolescent boys at risk for clinical or major depression (MD). The combination of high self-reported depressive symptoms and elevated morning cortisol increase the risk of MD by up to 14 times, according to a study published online Feb. 18 in Proceedings of the National Academy of Sciences. Early identification of this subtype of boys may lead to earlier diagnosis and treatment as MD in childhood, teen, or young adult years substantially raises the risk of episodes of depression later in life. In the study, self-reported depressive symptoms were measured using the 33-item version of the Moods and Feelings Questionnaire, while cortisol was measured by ELISA on 20-μl saliva samples without extraction. One cohort (n = 660) provided four early-morning samples on schooldays within a week and then again 12 months later, and depressive symptoms were measured at baseline, four months, eight months, and 12 months. The second cohort (n = 1,198) provided early-morning samples over three school days and measured depressive symptoms at baseline, 18 months, and 36 months. The researchers utilized these repeated measures of self-reported depressive symptoms and early-morning levels of cortisol (both known correlates to MD) to categorize […]