School Drug Prevention Program Reduced Marijuana Use Among Brazilian Teens Aged 13-15
A European school-based drug prevention program adapted for Brazil showed evidence of reducing marijuana use among 13-15 year olds, with 85.7% of intervention participants who were using marijuana transitioning to non-use.
Quick Facts
What This Study Found
Researchers evaluated the Unplugged program, a European school-based drug prevention curriculum, adapted for Brazilian public middle schools. The program had no measurable effect on 11-12 year olds, but showed promising results for 13-15 year olds.
Among 13-15 year old marijuana users, 85.7% in the intervention group transitioned from use to non-use, compared to only 28.6% in the control group (OR = 17.5). Students who received the program maintained their pre-program drug use levels, while control group students showed significant increases in marijuana use and binge drinking over the same period.
The program consisted of 12 weekly classes focused on life skills, social influence resistance, and knowledge about drugs.
Key Numbers
2,185 students in 16 schools across 3 cities. 12 weekly program sessions. Among 13-15 year old marijuana users, 85.7% of intervention participants stopped using vs 28.6% of controls (OR = 17.5, p = 0.039).
How They Did This
Non-randomized controlled trial conducted in 2013 with 2,185 students across 16 public schools in 3 Brazilian cities. The intervention group received 12 weekly Unplugged classes; the control group received no prevention programming. Multilevel analyses assessed changes in drug consumption over time and between groups.
Why This Research Matters
Most Brazilian schools lack structured drug prevention programs. This study demonstrates that a well-designed, culturally adapted program can reduce marijuana use among teens in the age group most likely to initiate use. The striking difference in transition rates (85.7% vs 28.6%) suggests meaningful impact.
The Bigger Picture
Drug prevention programs that focus on life skills and social influence resistance rather than scare tactics have shown the most consistent evidence of effectiveness. This study suggests such approaches can work across cultural contexts when properly adapted.
What This Study Doesn't Tell Us
Non-randomized design introduces potential selection bias. The marijuana user subgroup was small, making the 85.7% vs 28.6% comparison less reliable despite statistical significance. Short follow-up period. The control schools had no prevention programming at all, which inflates the apparent effect size compared to an active control.
Questions This Raises
- ?Would the effects persist beyond the study period?
- ?Would a randomized controlled trial confirm these findings?
- ?How much of the effect is due to the program versus attention and adult engagement?
- ?Would the program work in private schools or rural areas?
Trust & Context
- Key Stat:
- 85.7% of 13-15 year old marijuana users stopped using after the school program vs 28.6% of controls.
- Evidence Grade:
- Preliminary evidence from a non-randomized trial with promising but small-subgroup results. The lack of randomization and small marijuana user sample size warrant caution.
- Study Age:
- Published in 2016. School-based prevention programs continue to be evaluated and refined.
- Original Title:
- Efficacy evaluation of the school program Unplugged for drug use prevention among Brazilian adolescents.
- Published In:
- BMC public health, 16(1), 1206 (2016)
- Authors:
- Sanchez, Zila M(3), Sanudo, Adriana, Andreoni, Solange, Schneider, Daniela, Pereira, Ana Paula D, Faggiano, Fabrizio
- Database ID:
- RTHC-01257
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
Do school drug prevention programs work?
This study found that a skills-based program reduced marijuana use among 13-15 year olds in Brazil. Programs focused on life skills and resisting social pressure tend to be more effective than those relying on fear or information alone.
Why did the program only work for older teens?
The 11-12 year olds may have had too little drug exposure for prevention to show measurable effects, while the 13-15 year olds were in the age range where marijuana initiation typically begins, making prevention more relevant and measurable.
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Cite This Study
https://rethinkthc.com/research/RTHC-01257APA
Sanchez, Zila M; Sanudo, Adriana; Andreoni, Solange; Schneider, Daniela; Pereira, Ana Paula D; Faggiano, Fabrizio. (2016). Efficacy evaluation of the school program Unplugged for drug use prevention among Brazilian adolescents.. BMC public health, 16(1), 1206.
MLA
Sanchez, Zila M, et al. "Efficacy evaluation of the school program Unplugged for drug use prevention among Brazilian adolescents.." BMC public health, 2016.
RethinkTHC
RethinkTHC Research Database. "Efficacy evaluation of the school program Unplugged for drug..." RTHC-01257. Retrieved from https://rethinkthc.com/research/sanchez-2016-efficacy-evaluation-of-the
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.