Aims: To examine the effects of the 'Healthy School and Drugs' project, a Dutch school-based drug prevention project that was developed in the late 1980s and disseminated during the 1990s. This programme is currently being used by 64-73% of Dutch secondary schools and it is estimated that at least 350000 high school students receive this intervention each year.
Design, setting and participants: A quasi-experimental study in which students of nine experimental (N = 1156) schools were compared with students of three control schools (N = 774). The groups were compared before the intervention, 1 year later, 2 years later and 3 years later.
Measurements: Self-report measures of tobacco, alcohol and marijuana use, attitudes towards substance use, knowledge about substances and self-efficacy.
Findings: Some effects on the use of tobacco, alcohol and cannabis were found. Two years after the intervention, significant effects could still be shown on alcohol use. Effects of the intervention were also found on knowledge, but there was no clear evidence for any effects on attitude towards substance use and on self-efficacy.
Conclusions: This study shows the Healthy School and Drugs project as implemented in Holland may have some effect on drug use in the children exposed to it.