Challenges in implementing school-based drug prevention programs led by law enforcement officers

School-based prevention drug programs in the United States and Brazil are most commonly delivered by law enforcement officers (LEOs). However, limited research has explored challenges involved in the delivery of these interventions specifically related to their implementation by LEOs. We aim to describe the challenges affecting the implementation of school-based drug prevention programs delivered by LEOs. We conducted a qualitative study using 31 semi-structured interviews with LEOs who delivered the Brazilian version of the DARE-Keepin' it REAL program (fifth- and seventh-grade curriculum) and 8 focus groups with 80 students who participated in the program. All data were thematically analyzed. LEOs perceived devaluation from the police corporation, resulting in resource limitations and commanders' resistance to adapting schedules. Relationships with the school community posed additional challenges. Fifth graders seemed generally positive about LEOs' presence while seventh graders showed more negative responses. LEOs' street-level policing experiences influenced their approach to clarifying the consequences of drug use and willingness to share related experiences, even though this content is not part of the program. Therefore, it is crucial to consider alternative approaches to delivering preventive programs in schools, while simultaneously improving the training of LEOs already involved in program implementation to ensure alignment with evidence-based practices.