title: Heterogeneity of Depressive Symptom Trajectories through Adolescence: Predicting Outcomes in Young Adulthood.
abstract: OBJECTIVE
  This study describes developmental trajectories of depressive symptoms in adolescents and examines the association between trajectory group and mental health outcomes in young adulthood.
  
  
  METHODS
  Depressive symptoms were self-reported every three months from grade seven through grade 11 by 1293 adolescents in the Nicotine Dependence in Teens (NDIT) study and followed in young adulthood (average age 20.4, SD=0.7, n=865). Semi-parametric growth modeling was used to identify sex-specific trajectories of depressive symptoms.
  
  
  RESULTS
  THREE DISTINCT TRAJECTORY GROUPS WERE IDENTIFIED: 50% of boys and 29% of girls exhibited low, decreasing levels of depressive symptoms; 14% of boys and 28% of girls exhibited high and increasing levels; and 36% of boys and 43% of girls exhibited moderate levels with linear increase. Trajectory group was a statistically significant independent predictor of depression, stress, and self-rated mental health in young adulthood in boys and girls. Boys, but not girls, in the high trajectory group had a statistically significant increase in the likelihood of seeking psychiatric care.
  
  
  CONCLUSIONS
  Substantial heterogeneity in changes in depressive symptoms over time was found. Because early depressive symptoms predict mental health problems in young adulthood, monitoring adolescents for depressive symptoms may help identify those most at risk and in need of intervention.
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario ; Ontario Tobacco Research Unit, Toronto, Ontario.
authors.forename: Michael
authors.initials: M
authors.lastname: Chaiton
authors.forename: Gisèle
authors.initials: G
authors.lastname: Contreras
authors.forename: Jennifer
authors.initials: J
authors.lastname: Brunet
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Sabiston
authors.forename: Erin
authors.initials: E
authors.lastname: O'Loughlin
authors.forename: Nancy C P
authors.initials: NC
authors.lastname: Low
authors.forename: Igor
authors.initials: I
authors.lastname: Karp
authors.forename: Tracie A
authors.initials: TA
authors.lastname: Barnett
authors.forename: Jennifer
authors.initials: J
authors.lastname: O'Loughlin
keywords: adolescents; depressive symptoms; development; latent growth modeling; mental health