Stress-diathesis based predictors of depression and anxiety trajectories in adolescence: a population-based longitudinal cohort study

Background Adolescent mental health has worsened, and prevention efforts have become increasingly important. The purpose of this study was to examine longitudinal symptom trajectories of depression and anxiety throughout adolescence, in a contemporary sample. The stress-diathesis model was used to inform potential vulnerability factors and stressors associated with these trajectories. Methods Symptoms of depression and generalized anxiety were assessed in a school-based population sample of N=6102 adolescents (aged 13-14 at baseline). Growth mixture models across four time points were used to model longitudinal trajectories of symptoms. Multinomial regression was used to examine factors associated with each trajectory class. Results Of the full sample, 49.5% were female, 45.9% were male, and 4.6% were gender diverse. Four discrete classes for both depression and anxiety trajectories were identified, which comprised consistently low symptoms ('low'; 72.5% depression; 66.9% anxiety), consistently high symptoms ('high'; 11.5% depression; 18.4% anxiety), elevated symptoms that reduced over time ('decreasing'; 8.3% depression; 6.9% anxiety), and low-moderate symptoms that increased over time ('increasing'; 7.7% depression; 7.8% anxiety). Factors associated with poorer trajectories were being female or gender diverse, lower socioeconomic status, higher levels of neuroticism and lower levels of conscientiousness, greater adverse childhood experiences, higher levels of peer problems, bullying victimization, and negative family interactions. Conclusions A range of background vulnerabilities and specific stressors were associated with poorer depression and anxiety trajectories over a 3-year period. Prevention approaches may require policy and practice changes that promote more supportive family, school, and societal environments from childhood to adolescence.