The effectiveness of a school-based substance abuse prevention program: 18-Month follow-up of the EU-Dap cluster randomized controlled trial

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Abstract

Aim

To evaluate the effectiveness of a school-based substance abuse prevention program developed in the EU-Dap study (EUropean Drug Addiction Prevention trial).

Materials and methods

Cluster Randomized Controlled Trial. Seven European countries participated in the study; 170 schools (7079 pupils 12–14 years of age) were randomly assigned to one of three experimental conditions or to a control condition during the school year 2004/2005. The program consisted of a 12-h curriculum based on a comprehensive social influence approach. A pre-test survey assessing past and current substance use was conducted before the implementation of the program, while a post-test survey was carried out about 18 months after the pre-test. The association between program condition and change in substance use at post-test was expressed as adjusted prevalence odds ratio (POR), estimated by multilevel regression models.

Results

Persisting beneficial program effects were found for episodes of drunkenness (any, POR = 0.80; 0.67–0.97; frequent, POR = 0.62; 0.47–0.81) and for frequent cannabis use in the past 30 days (POR = 0.74; 0.53–1.00), whereas daily cigarette smoking was not affected by the program as it was at the short-term follow-up. Baseline non-smokers that participated in the program progressed in tobacco consumption to a lower extent than those in the control condition, but no difference was detected in the proportion of quitters or reducers among baseline daily smokers.

Conclusion

The experimental evaluation of an innovative school curriculum based on a comprehensive social influence approach, indicated persistent positive effects over 18 months for alcohol abuse and for cannabis use, but not for cigarette smoking.

Introduction

Substance use is a leading cause of premature mortality in developed countries. Attributable mortality for tobacco smoking ranges from 27% to 32% for men and from 4% to 7% for women in the Europe (Ezzati and Lopez, 2003). Alcohol is estimated to cause 14.6% of all premature deaths in European countries (Rehm et al., 2007). Overall substance use currently accounts for 31% of all deaths, 25% of potential years of life lost and in Canada, 19.5% of all hospital days for those under 70 years of age (Patra et al., 2007). Furthermore, the burden of diseases attributable to the use of alcohol and drugs seems to have increased in developed countries during the past decade, whereas a decrease is evident for that attributable to tobacco smoking.

Among 15–16-year-old students in those European countries participating in the European School Survey Project on Alcohol and Other Drugs (ESPAD) study, past 30-day prevalence of the use of these substances remained constant between 1999 and 2003. Minor exceptions include small reductions in cigarette smoking in some Nordic countries as well as in France, Ireland, Greece, and United Kingdom; small increases in the prevalence of frequent drunkenness in several Eastern European countries and in Italy; and increased figures for cannabis use in several Eastern countries and in the United Kingdom (Hibell et al., 2004).

Universal prevention in the school setting is one of the most feasible and appropriate strategies to tackle substance use among youth (UNICRI, 2003). However, the empirical evidence supporting efficacy of school programs is rather weak. Previous Cochrane reviews established that programs aiming to enhance social skills are effective in reducing drug use (Faggiano et al., 2005), but results for tobacco smoking and alcohol abuse were far less convincing (Thomas and Perera, 2006, Foxcroft et al., 2002). However, recent evaluations concluded that programs based on social influence approaches may also be effective in delaying the onset of smoking (Griffin et al., 2003, Crone et al., 2003, Campbell et al., 2008).

Nevertheless, several authors remain skeptical on the effectiveness of programs such as Life Skills Training (Botvin et al., 1980), criticizing either the low methodological quality of the evidence (Gorman, 2005, Gorman et al., 2007), or the occurrence of publication bias (McCambridge, 2007). Criticism also seems to concern the comprehensive social influence approach, which combines the training of social skills to resist the pressure to use substance while advancing knowledge on risks, and normative education (Evans, 1976). Skepticism towards programs’ efficacy may be one of the reasons why in Europe the diffusion of school interventions based on social skills is inconsistent (EMCDDA, 2007, and related country reports www.emcdda.europa.eu).

The EU-Dap (EUropean Drug Addiction Prevention) study was designed to evaluate the effectiveness of an innovative school-based program for the prevention of substance use in European junior high schools. Short-term post-test results have been published elsewhere (Faggiano et al., 2008) and address the evaluation of the program's effects at the end of the year after its conclusion.

Section snippets

Methods

The EU-Dap study consisted of a four-arm experimental evaluation comparing an innovative school curriculum with usual curricula (control condition). The study was carried out simultaneously in Austria, Belgium, Germany, Greece, Italy, Spain and Sweden.

Program implementation

55% of the enrolled classes implemented all the units in the curriculum, while 66% received at least 10 units and 77% at least six. Less than 5% of the classes failed to implement any part of the curriculum. On average, each unit was taught to 78% of the target population. This level of program implementation is comparable to that of other curricula administered in a European setting (Stead et al., 2007). The degree of implementation of the peer program was low in all centres. Very few classes

Discussion

Unplugged is an innovative school program based on the Comprehensive social influence approach (Sussman et al., 2004), incorporating life skills elements, and is designed to delay or prevent the onset of substance misuse among junior high school students. This program has been evaluated using a large cluster randomized trial, involving nine centres, 170 schools and approximately 7000 students in seven European countries.

15 months after the completion of the program, exposure to Unplugged was

Role of funding source

EU-Dap is a project funded by the European Commission (European Public Health Program 2002 grant # SPC 2002376 and Program of Community Action in the field of Public Health 2003–2008 grant # SPC 2005312). Additional national funding was provided by: Compagnia di San Paolo (grant # 2002-0703) and Lega Italiana per la Lotta contro i Tumori (grant # 2003 43/4) for the Novara centre, Swedish Council for Working Life and Social Research (grant # 2002-0979), Stockholm County Council (Public Health

Contributors

FF, RG, CR and KB designed the study. FF and FVT drafted the paper. FF, FVT, GB, CR, RG and RS contributed to revising the paper. FVT, LC and DG undertook the data analysis. All other authors and members of the EU-Dap Study Group carried out the intervention and collected the data. All authors contributed to and have approved the final manuscript.

Conflict of interest

All authors declare that they have no conflicts of interest.

Acknowledgements

Thanks to Barbara Zunino and Valeria Siliquini for the administrative management of the project. We wish to acknowledge the following persons at the national centres for their contribution to the field work and data collection: Samuela Bighiani, Alessandro Lanszweert, Paride Angius, Domenico Bernardi, Flavio Colacito, Rossella Gigante, Stefania Passerini and Laura Vitale at the Italian centres; Regina Fenk, Elke Lantschik, Alexander Bohrn and Margot Koller, who also contributed to the design of

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    EU-Dap Study Group: Roberta Siliquini, Barbara Zunino, Luca Cuomo, Federica Vigna-Taglianti, Serena Vadrucci, Laura Vitale (Piedmont Centre for Drug Addiction Epidemiology – Turin, Italy); Peer van der Kreeft (De Sleutel – Gent, Belgium); Juan Carlos Melero, Laura Varona (EDEX – Bilbao, Spain); Gudrum Wiborg (IFT-Nord – Kiel, Germany); Clive Richardson (University Mental Health Research Institute – Athens, Greece); Maro Vassara (Pyxida – Thessaloniki, Greece); M. Rosaria Galanti, Sara Sanchez and Lotta Jansson (Dept. of Public Health Sciences, Karolinska Institutet – Stockholm, Sweden, formerly of the Stockholm Centre of Public Health); Gregor Burkhart (EMCDDA – Lisbon, Portugal); Fabrizio Faggiano, Massimiliano Panella (Dept of Clinical and Experimental Medicine, Avogadro University – Novara, Italy); Leila Fabiani, Maria Scatigna (Dept of Internal Medicine and Public Health – University of L’Aquila – L’Aquila, Italy).

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