Trajectories of depressive symptoms through adolescence and young adulthood: social and health outcomes.

Depressive symptoms display heterogeneous trajectories across adolescence, which can lead to different consequences. This study aimed to identify trajectories of depressive symptoms from adolescence to young adulthood, assessing the association with social and health outcomes at young adulthood. Adolescents born in 1990, enrolled in schools of Porto, Portugal, in 2003-2004 (EPITeen study) completed the Beck Depression Inventory II (BDI-II) at 13, 17 and 21 years. Mixed models and model-based clustering were used to describe the trajectories in the BDI-II score (n = 2010). Outcomes were assessed at age 21 years with self-administered questionnaires and face-to-face interviews (n = 1594). Odds ratios or regression coefficients, with 95% confidence intervals, were estimated using logistic and linear regression. Three trajectory classes of depressive symptoms were identified, similar in shape in both sexes: High (8.4%), Moderate (31.3%) and Low (60.2%). Participants in High or Moderate classes were more likely to describe lower scores of community involvement, more medical appointments during the last year, higher levels of pain and had higher probability of self-rating health as "good" or "fair or poor". Females in the High and Moderate classes were more likely to be current smokers, to describe ever using drugs and to report more sexual partners, emergency room visits and the use of antidepressants. The risk of depressive symptoms in adulthood is likely to be early determined in adolescence. The trajectory classes with higher levels of symptoms were associated with worse social and health outcomes.