Major depressive disorder (MDD) is a relatively common yet clinically heterogeneous disorder for which there exists no validated biomarkers in the youth population to aid the detection of at-risk groups for depression in general and for young males in particular.
Using repeated measurements of two well-known correlates of MDD (self-reported current depressive symptoms and early-morning cortisol), the authors of this study undertook a population-based investigation to ascertain subtypes of adolescents that represent separate longitudinal phenotypes.
Through the use of latent class analysis, they revealed a high-risk subtype (17% of the sample) demarcated by both high depressive symptoms and elevated cortisol levels. Membership of this class of individuals was associated with increased levels of impaired autobiographical memory recall in both sexes and the greatest likelihood of experiencing MDD in boys only. These previously unidentified findings demonstrate at the population level a class of adolescents with a common physiological biomarker specifically for MDD in boys and for a mnemonic vulnerability in both sexes. The authors suggest that the combination of high depressive symptoms and elevated morning cortisol is particularly hazardous for adolescent boys.
Owens M, Herbert J, Jones PB, Sahakian BJ, Wilkinson PO, Dunn VJ, Croudace TJ, Goodyer IM: Elevated morning cortisol is a stratified population-level biomarker for major depression in boys only with high depressive symptoms. PNAS 111(9):3638-3643 (2014).
