摘要：Objectives. We examined whether the Communities That Care (CTC) system sustained effects 1.5 years after study funding ended on prevention system constructs expected to be important for community-level reductions in drug use and antisocial behaviors among youths. Methods. Data were from a community trial of 24 towns in the United States randomized to either the CTC intervention or control conditions. Participants were 928 community key leaders interviewed at 1 to 4 waves from 2001 to 2009. Intervention activities, including training and technical assistance, were conducted between 2003 and 2008 in the CTC communities. Results. Leaders from CTC communities reported higher levels of adoption of a science-based approach to prevention and a higher percentage of funding desired for prevention activities in 2009 than did leaders in control communities. CTC communities showed a higher increase over time in community norms against adolescent drug use as well as adoption of a science-based approach compared with control communities. Conclusions. These findings indicated that CTC implementation produced enduring transformation of important prevention system constructs in intervention communities, which might, in turn, produce long-term reductions in youth problem behaviors. Despite evidence for effectiveness of preventive interventions to reduce the occurrence of drug use and delinquent behaviors among youths, 1,2 few communities have implemented such interventions as part of community-wide strategies. Approaches that address prevention of youth problem behaviors through community system-level changes have the potential for significant public health impact. 3–5 Consistent with this, the federal government identified systems thinking and evidence-based practices, research, and evaluation as 2 priorities for public health improvement for the next decade. 6 A recent review identified that a common feature of successful strategies for reducing alcohol use or availability of alcohol to adolescents is reliance on local coalitions to develop and implement prevention plans. 5 For example, Communities Mobilizing for Change on Alcohol (a program using coalition-based efforts to change community policies, practices, and norms related to underage alcohol use) showed a reduction of alcohol provision to minors and arrests for drunk driving among 18- to 20-year-old drivers. 7,8 The Midwestern Prevention Project, which combined coalition-led strategies with school-based prevention activities, demonstrated reductions in past-month cigarette and alcohol use among middle school students. 9 Not all coalition-based efforts have proven successful, however. For example, the Fighting Back 10 and Community Partnership 11 initiatives did not yield reductions in youth alcohol use. Insufficient guidance on implementing prevention strategies and reliance on locally created prevention programs not tested for effectiveness likely played roles in the lack of effects. A coalition-based community strategy that showed significant effects on youth outcomes is Communities That Care (CTC). 12,13 CTC is a manualized system to mobilize communities to develop and transform their prevention systems to address elevated risk and depressed protective factors for youth problem behaviors through the appropriate selection, installation, and monitoring of tested and effective preventive interventions. 14,15 According to the CTC theory of change, CTC implementation leads to reduced problem behavior and positive development among youths through activating and reinforcing 5 prevention system constructs: adoption of a science-based approach to prevention, 16 community support for prevention, 17,18 community norms against adolescent drug use, 19 collaboration across community service sectors for prevention, 20,21 and use of the social development strategy. 22 Although each construct is theorized to be important, 23–26 adoption of a science-based approach to prevention, which refers to community leaders’ understanding and use of a prevention science framework to plan and implement programs to prevent youth problem behaviors, 16 is the primary mechanism through which CTC is expected to produce positive changes in outcomes. 27 Findings from the Community Youth Development Study (CYDS), a community-randomized controlled trial designed to test the efficacy of CTC, 12,13 were consistent with this theory of change. Previous studies found positive effects of CTC on prevention system constructs. Earlier CYDS findings showed that CTC compared with control community leaders reported higher levels of adoption of a science-based approach to prevention in 2004 and 2007, 1.5 and 4.5 years after initial CTC implementation, respectively. 28,29 Also, at 4.5 years after implementation, leaders from CTC compared with control communities reported a higher percentage of funding desired for prevention activities and, among communities with higher proportions of residents in poverty, higher levels of community norms against adolescent drug use. As CTC communities transformed their prevention systems, risk factors for problem behaviors that were selected by CTC communities to be targeted for intervention were also affected. 30,31 Using data from a sample of youths followed longitudinally from fifth through eighth grades over a corresponding time period (2004–2007) from the same randomized CYDS communities, studies demonstrated a slower growth of levels of targeted risk factors among youths from CTC compared with control communities. 30,31 Finally, data from these longitudinal studies showed that positive youth outcomes were achieved. Compared with those from control communities, CTC youths were less likely to initiate delinquent behavior and use of alcohol, cigarettes, and smokeless tobacco; were less likely to use alcohol and smokeless tobacco in the past month and to binge drink in the past 2 weeks; and reported fewer past-year delinquent behaviors. 30,31 Recent research from the CYDS longitudinal sample assessed during 10th grade, 1 year after the removal of study funding and resources for intervention to CTC communities, showed that youths from CTC compared with youths from control communities continued to have a reduced risk of initiation of alcohol and cigarette use and delinquent behavior, lower prevalence of current smoking and past-year delinquent behavior, and lower levels of risk factors targeted by communities. 32 These findings indicated that the effects of interventions implemented through CTC during the study period were sustained for a year beyond funding. An important next question was whether CTC’s effects on prevention systems were also sustained. Data from previous CYDS analyses of prevention system characteristics were collected while CTC communities were receiving study-funded intervention resources. The time shortly after removal of funding was an important period in the long-term viability of this intervention. Because of challenges with competing demands and sustaining momentum, interventions often cease after withdrawal of study funding. 33,34 Without study resources, will CTC communities abandon the use of science to guide prevention strategies or decrease their commitment to prevention efforts? Is an initial round of CTC training and implementation sufficient to generate sustained system-wide changes in prevention systems that have potential for continued long-term reductions in youth problem behaviors? As a follow-up to previous studies and as part of the ongoing CYDS, this study examined whether CTC’s effects on prevention system constructs were sustained through 2009—approximately 6.5 years after initial implementation, 2 years after the previous data collection, and 1.5 years after study resources for CTC implementation were withdrawn. This study also examined whether effects of CTC on prevention system constructs differed by community-level characteristics, including percentage of residents living in poverty, percentage of non-White residents, and population size.
