An impact evaluation showed that the program resulted in a 50% increase in seventh-grade students’ intention to use cigarettes and a 38% increase in the likelihood of accepting cannabis, compared to those who did not participate in the program. The study found a small positive effect on students’ evaluation of their school experience, although without statistical significance [1].
Fifth-graders showed a slight reduction in decision-making skills compared to the treatment group. The study indicates that the program produced side effects, worsening students’ intention to use drugs; it is highly recommended that large-scale implementation be rethought, and it is very important to conduct new experiments to qualify the evidence [1].
A second impact evaluation study found no evidence of the program’s efficacy, indicating its ineffectiveness as a universal program to delay or reduce any drug abuse after 9 months [2].
In addition, a negative effect was observed in the specific subgroup of seventh-graders who were already binge-drinkers and received the intervention. In this case, it was observed that these students were significantly more likely to maintain this behavior compared to the control group [2].
The first study had an experimental design conducted in 30 public schools in the city of São Paulo, with 1,727 fifth-graders and 2,303 seventh-graders from elementary schools, separated between the group that received the 10 PROERD sessions and another group with the same characteristics that served as a control group, which did not participate in the program [1]. The second experiment had a sample of 4,030 students from 30 public schools in the state of São Paulo (1,727 fifth-graders and 2,303 seventh-graders) [2].