[Process evaluation of the school-based cannabis use prevention program "xkpts.com" in adolescents from Barcelona in...

The observed positive effects of school-based prevention programs are frequently lower than what was expected, usually due to inadequate implementation.

To describe the process evaluation of a cannabis use school-based prevention program (xkpts.com), to measure teachers' satisfaction with the program and to define quantitative and qualitative parameters for assessing the exhaustiveness of the intervention.

Cross-sectional descriptive study.

117 9th-grade classes in 39 schools (2812 students). The information was gathered by means of a self-report questionnaire for teachers and families. A descriptive analysis was made of the implementation of the intervention in the classrooms and of the families' participation.

Teachers' response rate was 65%. Discussion was the method most widely applied (100% of the classrooms) and DVD was the most widely used material (93.4%). Skills training was applied in 72.4% of the classrooms. In 59.2% of the classrooms there was an acceptable intervention (at least 8 of the 16 preventive activities), while in 38.2% there was a qualified intervention (at least 1 activity for each general lesson and 2 for each specific one). Mean score given to the program by teachers was 7.4, and 81.6% of them reported their intention to apply it again. Participation rate of the students' families was 28.3% (796).

The intervention was acceptable in two out of three classrooms, while in four out of ten the protocol was applied strictly. Greater participation of the students' families corresponded to those schools in which the intervention was better implemented.