Prevention bends adolescent internalizing trajectories: Within-person changes from pre- to post-prevention

To evaluate whether depression prevention programs can reduce adolescents' within-persons' depression and anxiety symptoms from pre-prevention assessed levels, which were obtained via naturalistic repeated measures for 1-year before randomization and intervention delivery, to post-prevention levels ascertained through 21-months follow-up.

This randomized controlled trial included 204 adolescents (mean [SD] age 14.26 [1.65] years; 56.4 % female). Prior to delivery of interventions (Coping With Stress, cognitive-behavioral program, or Interpersonal Psychotherapy-Adolescent Skills Training, interpersonal program), youths' depression and anxiety symptoms were assessed every 3-months for 1-year naturalistically to establish pre-prevention symptom levels. Then, youth participated in preventive interventions and had internalizing symptoms outcomes measured repeatedly through 3-months follow-up and then longer-term through 21-months follow-up.

Longitudinal slopes of youths' pre-prevention depression (b = -0.30, p = .004) and anxiety (b = -0.54, p = .013) symptoms naturalistically decreased across 4 time points from -12-months through -3-months assessments. Compared to -12-months pre-prevention symptom levels, preventive interventions significantly decreased within-person symptoms of depression (d = 0.67 [0.39,0.95], p < .001 at 3-months follow-up; d = 0.45 [0.17,0.73], p < .001 at 21-month follow-up) and anxiety (d = 0.88 [0.59,1.16], p < .001 at 3-months follow-up; d = 0.74 [0.45,1.02], p < .001 at 21-months follow-up).

This study used a novel head-to-head comparative effectiveness trial design with repeated internalizing symptoms assessments prior to randomization and interventions delivery to evaluate how much prevention can adjust within-person symptom changes over time and shift symptoms from pre-prevention ascertained levels to lowered post-prevention levels maintained across follow-ups. Findings support the utility of evidence-based depression prevention programs to bend individuals' internalizing symptom trajectories when anxiety and depression levels normatively rise throughout adolescence.

Bending Adolescent Depression Trajectories Through Personalized Prevention; https://www.

gov/; ClinicalTrials.gov (NCT019148167) Insitutional review boards of both study sites approved all procedures.