Background: The high prevalence of major depressive disorder in adolescents and the low rate of successful treatment highlight a pressing need for accessible, affordable adolescent depression prevention programs. The Internet offers opportunities to provide adolescents with high quality, evidence-based programs without burdening or creating new care delivery systems. Internet-based interventions hold promise, but further research is needed to explore the efficacy of these approaches and ways of integrating emerging technologies for behavioral health into the primary care system. Methods/Design We developed a primary care Internet-based depression prevention intervention, Competent Adulthood Transition with Cognitive Behavioral Humanistic and Interpersonal Training (CATCH-IT), to evaluate a self-guided, online approach to depression prevention and are conducting a randomized clinical trial comparing CATCH-IT to a general health education Internet intervention. This article documents the research framework and randomized clinical trial design used to evaluate CATCH-IT for adolescents, in order to inform future work in Internet-based adolescent prevention programs. The rationale for this trial is introduced, the current status of the study is reviewed, and potential implications and future directions are discussed. Discussion The current protocol represents the only current, systematic approach to connecting at-risk youth with self-directed depression prevention programs in a medical setting. This trial undertakes the complex public health task of identifying at-risk individuals through mass screening of the general primary care population, rather than solely relying on volunteers recruited over the Internet, and the trial design provides measures of both symptomatic and diagnostic clinical outcomes. At the present time, we have enrolled N = 234 adolescents/expected 400 and N = 186 parents/expected 400 in this trial, from N = 6 major health systems. The protocol described here provides a model for a new generation of interventions that blend substantial computer-based instruction with human contact to intervene to prevent mental disorders such as depression. Because of the potential for broad generalizability of this model, the results of this study are important, as they will help develop the guidelines for preventive interventions with youth at-risk for the development of depressive and other mental disorders. Trial registration Clinical Trial Registry: NCT01893749 date 6 May 2012
