Community-based efforts to prevent substance use, delinquency, and violence are an essential component of promoting health during adolescence and later life.^1,2 Communities That Care (CTC) is a prevention system that activates a coalition of stakeholders to develop and implement a science-based approach to prevention in the community to achieve collective impact on youth development community wide.^3,4 The CTC prevention system seeks to achieve this goal by increasing the use of tested, effective preventive interventions that address risk factors for adolescent problem behaviors prioritized by the community. This is expected to produce community-wide reductions in targeted risk factors and, in turn, decreased adolescent substance use, delinquency, and violence.^3,5

ObjectiveTo test whether the Communities That Care (CTC) prevention system reduced levels of risk and adolescent problem behaviors community-wide 6 years after installation of CTC and 1 year after study-provided resources ended.DesignA community randomized trial.SettingTwenty-four small towns in 7 states, matched within state, randomly assigned to control or intervention condition in 2003.ParticipantsA panel of 4407 fifth-grade students was surveyed annually through 10th grade from 2004 to 2009.InterventionA coalition of community stakeholders received training and technical assistance to install CTC, used epidemiologic data to identify elevated risk factors and depressed protective factors in the community, and implemented programs to address their community's elevated risks from a menu of tested and effective programs for youths aged 10 to 14 years, their families, and schools.Outcome MeasuresLevels of risk and incidence and prevalence of tobacco, alcohol, and other drug use; delinquency; and violent behavior by grade 10.ResultsMean levels of targeted risks increased less rapidly between grades 5 and 10 in CTC than in control communities and were significantly lower in CTC than control communities in grade 10. The incidence of delinquent behavior, alcohol use, and cigarette use and the prevalence of current cigarette use and past-year delinquent and violent behavior were significantly lower in CTC than in control communities in grade 10.ConclusionsUsing the CTC system can produce enduring reductions in community-wide levels of risk factors and problem behaviors among adolescents beyond the years of supported implementation, potentially contributing to long-term public health benefits.Trial Registrationclinicaltrials.gov Identifier: NCT01088542