ABSTRACT By the end of high school, close to half of 12th graders report marijuana use. While youth often perceive marijuana use as low risk, particularly as more states legalize marijuana for recreational and medical use, there are serious consequences of use by adolescents, including neurological impairment, mental health issues, and future dependence. Many current school-based drug prevention programs are not evidence-based, struggle with fidelity of implementation, and do not meet current curriculum standards. As an effective, engaging, and scalable school-based digital prevention program, Click City®: Marijuana will address the weaknesses of existing programs. Click City®: Marijuana, designed for 8th grade students with a 9th grade booster, will focus on preventing or decreasing youth use of marijuana. The program will target all common methods of marijuana consumption by youth, including vaping, smoking, dabbing, and edibles, and program content development will be guided by theory. The proposed program builds on our team's development of two other effective school-based substance prevention programs, targeting alcohol and tobacco use. Multiple school administrators have asked us to develop a similar, evidence-based, digital marijuana prevention program, as they are seeing an increase in student marijuana use, particularly by vaping. Click City®: Marijuana will be developed iteratively in collaboration with students from across the country, as well as with an Advisory Board of key stakeholders. It will be delivered online and accessible across devices and platforms, ensuring scalability and fidelity of program implementation. Further, we will empirically evaluate each program component to assure efficacy prior to inclusion in the final program, thus increasing effectiveness. Within this Phase I project, we propose to accomplish the following aims: 1) Storyboard potential program components with focus groups of 8th grade students and create a short introductory module; 2) Develop two program components targeting specific risk factors predictive of use of marijuana, informed by an iterative development process including focus and user testing with our target population and consultations with our Advisory Board; and 3) Conduct a rigorous evaluation of the two new components, using a crossover design, hypothesizing that each component will change the risk factor it was designed to change, and will decrease intentions and willingness to use marijuana in the future. If these components are acceptable, engaging, and satisfactory for users, and if they change the targeted etiological mechanisms, this will support the feasibility of the Phase II study. Phase II plans include developing the rest of the components and conducting a short-term effectiveness trial to evaluate the 8th grade program. As technology in schools is now commonplace, the proposed program has high commercial value. Click City®: Marijuana has the potential to reach millions of adolescents across the country, preventing serious neurological, mental health, and dependence issues by delaying, decreasing, or preventing early marijuana use.

Project Narrative The overarching goal of the proposed research is to create an effective, engaging, and scalable school-based digital prevention program for 8th and 9th grade students, Click City®: Marijuana, to prevent or decrease use of marijuana. Within this Phase I study, we will collaborate with students and an Advisory Board of key stakeholders to storyboard program components, develop two components that target etiological mechanisms that precede use of marijuana, and rigorously evaluate the two developed components. Click City®: Marijuana will address limitations of existing prevention programs, and has great commercial potential as part of school curricula.