Dutch School-Based Drug Prevention Program Had No Effect on Teen Substance Use | Research

The takeaway

A large randomized trial found that the Healthy School and Drugs prevention program did not reduce alcohol, tobacco, or marijuana use among Dutch adolescents.

Read this if you want to know whether school drug prevention programs actually reduce substance use.

3,784 students, 23 schools, 32-month follow-up: no effects on any substance

What the researchers found

Across all measures and both intervention conditions (e-learning and integral), the Healthy School and Drugs program showed no statistically significant effects on preventing new cases of alcohol, tobacco, or marijuana use at 32 months follow-up.

The program was tested in two formats: an e-learning version (digital lessons only) and an integral version (digital lessons plus school policy and parental involvement). Neither version outperformed the control condition for any substance.

Specifically, lifetime marijuana prevalence showed no differences between either intervention condition and controls (e-learning: B = 0.070, P = 0.732; integral: B = 0.186, P = 0.214). Similar null findings were observed across all alcohol and tobacco measures.

Why it matters

This study is a reminder that well-intentioned prevention programs do not always work. The null result raises questions about whether the specific program content, delivery method, or implementation quality was insufficient, or whether school-based prevention programs in general face fundamental challenges in changing adolescent substance use behavior.

The numbers in context

3,784 students across 23 schools. Follow-up at 32 months. No significant effects on lifetime or 1-month prevalence of alcohol, tobacco, or marijuana use in either intervention condition.

How the study worked

This was a randomized clustered trial involving 3,784 students aged 11-15 across 23 Dutch secondary schools. Schools were randomly assigned to one of three conditions: e-learning intervention, integral intervention (e-learning plus school policy and parent components), or control. Students completed digital questionnaires before the intervention and at 32-month follow-up. The primary outcomes were new incidences of substance use.

What this study cannot tell us

The study measured incidence (new use) rather than changes in frequency among existing users. The 32-month follow-up may have missed shorter-term effects that faded. Implementation quality across schools was not closely monitored, and the authors note the program may have been implemented inadequately at some sites.

How to read the evidence

This is a well-powered randomized clustered trial with long follow-up, representing strong evidence that this particular program was ineffective.

When this study was published

Published in 2014. Research on school-based prevention continues, with increasing focus on identifying which program components are most effective.

The bigger picture

School-based substance use prevention programs have a mixed track record. While some programs have shown modest effects, many well-designed evaluations find null results. These findings highlight the importance of rigorous evaluation before implementing prevention programs at scale and the need to identify what program elements actually drive behavior change.

Questions still open

What elements distinguish effective school-based prevention programs from ineffective ones? Would more intensive implementation support improve outcomes? Are there subgroups of students who benefited despite null overall effects?

Common questions

Does this mean all school drug prevention programs are ineffective?

Not necessarily. This study evaluated one specific program. Other programs with different approaches, such as social-emotional learning or motivational interviewing components, have shown positive effects in some trials.

What is a clustered randomized trial?

In a clustered trial, groups (in this case, schools) rather than individuals are randomly assigned to conditions. This prevents contamination between treatment and control students within the same school.

Read the original research

Effectiveness of the 'Healthy School and Drugs' prevention programme on adolescents' substance use: a randomized clustered trial.

Addiction (Abingdon, England), 109(6), 1031-40

View on PubMed ↗Publisher’s paper ↗

Citation

Malmberg, Monique; Kleinjan, Marloes; Overbeek, Geertjan; Vermulst, Ad; Monshouwer, Karin; Lammers, Jeroen; Vollebergh, Wilma A M; Engels, Rutger C M E. (2014). Effectiveness of the 'Healthy School and Drugs' prevention programme on adolescents' substance use: a randomized clustered trial.. Addiction (Abingdon, England), 109(6), 1031-40. https://doi.org/10.1111/add.12526