With more than 13% of adolescents diagnosed with depressive disorders each year, prevention of depressive disorders has become a key priority for the National Institute of Mental Health (NIMH). Unfortunately, the investigators have no widely available interventions to reduce morbidity and mortality (e.g. public health impact). To address this need, the investigators developed a multi-health system "collaboratory" to develop and evaluate the primary care based technology "behavioral vaccine," Competent Adulthood Transition with Cognitive-Behavioral Humanistic and Interpersonal Therapy (CATCH-IT) (14 adolescent, 5 parent modules). Using this health-system collaboratory model, the full CATCH-IT program (all modules), demonstrated evidence of efficacy in prevention of depressive episodes in phase-three clinical trials in the United States and China. However, like many "package" interventions, CATCH-IT became larger and more complex across efficacy trials. Thus, adolescents were less willing to complete all 14 modules, suggesting adolescent dose "tolerability" issues (e.g., satisfaction, acceptability and resource use, "time as cost"). Similarly, primary care practices have "scalability" challenges (acceptability, feasibility, resource use, cost), resulting in declining REACH (percent of at-risk youth who complete intervention). To prepare for implementation studies and dissemination, the investigators need to address adolescent tolerability and practice/health system scalability, while preserving efficacy. Multiphase Optimization Strategy (MOST) uses a systematic analytic approach and a factorial randomized clinical trial design to address efficacy, tolerability, and scalability, simultaneously. The investigators will use a MOST approach to optimize CATCH-IT for the prevention of depression (indicated prevention, i.e., elevated symptoms of depression) in practices and health systems representative of US geography and population. The theoretically grounded components of CATCH-IT selected for study and optimization include: behavioral activation, cognitive-behavioral therapy, interpersonal psychotherapy, and parent program. The investigators will use a 4-factor (2x2x2x2) fully crossed factorial design with N=16 cells (25 per cell, 15% dropout) to evaluate the contribution of each component. The investigators propose to randomize N=400 adolescents from multiple sites: Advocate-Aurora Health Care (n=200); Lurie Children's Hospital (n=70); NorthShore University HealthSystem (n=70); University of Chicago Comer Hospital (n=25); University of Texas (n=20); University of Illinois College of Medicine Peoria (n=15). The at-risk youth will be high school students 13 through 18 years old, not currently experiencing a mood disorder, but with subsyndromal symptoms of depression (moderate to high risk). Using the efficient factorial design, the investigators can assess the contribution to prevention efficacy of each component. Thus, the MOST study design will enable us to eliminate non-contributing components while preserving efficacy and to optimize CATCH-IT by strengthening tolerability and scalability by reducing "resource use." By reducing resource use, the investigators anticipate satisfaction and acceptability will also increase, preparing the way for an implementation trial and eventual US Preventive Services Task Force endorsement to support dissemination. Thus, the primary question is whether one component, or perhaps two, can demonstrate an equivalent effect to combinations of other components in terms of efficacy, whilst also demonstrating superior adolescent/family tolerability scalability over a 12-month follow-up.