The effects of drug abuse prevention at school: the ‘Healthy School and Drugs’ project

INTRODUCTION

Over the past 30 years, three phases can be distinguishedin the development of school-based drug prevention programmes (Moskowitz 1989; Perry & Kelder 1992;Gorman 1995). In the first phase (early 1960s to early1970s), the programmes were focused largely on the provision of knowledge about drugs and the risks ofdrug use. During the second phase (early 1970s to early1980s), so-called affective programmes predominated.Most of these programmes were not drug-specific butconcentrated on broader issues of personal developmentsuch as decision-making, values clarification and stress-management (Gorman 1995). In the third phase (early1980s to date), the social influence model has dominatedschool-based drug prevention programmes. In this

model, resistance skills are developed, sometimes in com-bination with broader personal and social skills (includ-ing components of stress reduction and decision-making;Botvin et al. 1990).

During the three phases of programme development,several hundred studies investigated the effects of drugprevention programmes and several dozen of these havebeen found to be methodologically well-designed studies(Tobler et al. 2000). It has been well established in thesestudies that school-based prevention programmes canresult in significant increases in knowledge about sub-stances and in improved attitudes towards substance use.Furthermore, interventions that use interactive methodsmay have significant effects on substance use (Tobler et al.2000). The effects of most interventions on substance useare relatively small, but more sophisticated and extensive

© 2002 Society for the Study of Addiction to Alcohol and Other Drugs Addiction, 97, 67–73

The effects of drug abuse prevention atschool: the ‘Healthy School and Drugs’project

Pim Cuijpers1, Ruud Jonkers2, Inge de Weerdt 2 & Anco de Jong1

Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht1 and Rescon Research & Consultancy, Haarlem,The Netherlands2

Correspondence to:

Pim Cuijpers PhDTrimbos InstituteNetherlands Institute of Mental Health andAddictionPO Box 7253500 AS UtrechtThe Netherlands Tel.: + 31 30 297 11 00Fax: + 31 30 297 11 11E-mail: [email protected]

Submitted 21 February 2001;initial review completed 3 May 2001;final version accepted 23 August 2001

ABSTRACT

Aims To examine the effects of the ‘Healthy School and Drugs’ project, a Dutchschool-based drug prevention project that was developed in the late 1980s anddisseminated during the 1990s. This programme is currently being used by64–73% of Dutch secondary schools and it is estimated that at least 350 000high school students receive this intervention each year.Design, setting and participants A quasi-experimental study in which studentsof nine experimental (N = 1156) schools were compared with students of threecontrol 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 onalcohol use. Effects of the intervention were also found on knowledge, but therewas no clear evidence for any effects on attitude towards substance use and onself-efficacy.Conclusions This study shows the Healthy School and Drugs project as imple-mented in Holland may have some effect on drug use in the children exposedto it.

KEYWORDS Drug prevention, effect study, schools.

RESEARCH REPORT

68 Pim Cuijpers et al.


programmes can have moderate to large effects on sub-stance use. Examples of programmes with more robustand larger effects are life skills training (Botvin et al. 1995)and the school-based interventions from Project North-land (Perry et al. 1996; Williams et al. 1999).

One major challenge for substance use programmes inthe next decade is the dissemination of effective interven-tions in the daily practice of schools. Many of the mosteffective prevention programmes have been developed inresearch settings and do not fit easily within the schoolsystem, because of the large number of sessions and therequirements of scientific research. Other programmesare disseminating widely in daily practice in schools, butare not effective in reducing substance abuse. The mostwell-known example of this is the DARE programme. Thisis the most widely used drug prevention programme in theUnited States, but many well-designed studies have shownthat it has no significant effects on substance abuse (Ennetet al. 1994; Clayton, Cattarello & Johnstone 1996; Lynamet al. 1999). The next major step in drug abuse preventionhas to be the dissemination of effective prevention pro-grammes and the results of the scientific knowledge basethat has been built up in recent decades.

In the Netherlands, a drug prevention programmewas developed in the late 1980s, which was widely dis-seminated among schools during the 1990s. This pro-gramme, which is called ‘The Healthy School and Drugs’,is used at this moment by 64–73% of Dutch secondaryschools. It is estimated that each year at least 350 000high school students in the Netherlands receive thisintervention. This high level of dissemination has been reached by close cooperation with schools in thedevelopment of the intervention, and by building strongrelationships with local prevention specialists and localauthorities. These local prevention specialists are responsible for the dissemination of the programme inthe schools in their area and for supporting schools in theuse of the programme. They are backed up by a team ofspecialists, working on a national level.

In this paper, we describe the results of a quasi-experimental study examining the effects of the ‘HealthySchool and Drugs’ project (Jonkers et al. 1999).

METHOD

Participants and procedure

Nine experimental schools were compared to three con-trol schools. The experimental schools were recruited infive regions of municipal health services in theNetherlands. In order to be included in the study, theyhad to have an active committee coordinating the drugprevention activities at the school. This committee is one

of the basic components of the ‘Healthy School andDrugs’ projects. Furthermore, the schools had to conductprevention activities at several levels but at least at classroom level (the lessons). The control schools wererecruited from the same regions. They had to agree thatthey would not conduct the ‘Healthy School and Drugs’project during the following 3 years.

There were four measurement points, one before theintervention started (M0), 1 year later (M1), 2 years later(M2) and 3 years later (M3). Between each of the mea-surement points one part of the intervention was con-ducted in the experimental schools. Between M0 and M1

the intervention was aimed at tobacco, between M1 andM2 at alcohol and between M2 and M3 at cannabis.

Nineteen hundred and thirty subjects returned thequestionnaires at M0. Basic characteristics of the sampleare presented in Table 1.

Seventy-three per cent (N = 1405) of the originalsample (N = 1930) were interviewed at the four mea-surement points. One experimental school was excludedat M3 because it had ceased to work with the lessons ofthe project. The exact numbers of students at each measurement point are presented in Table 2.

Measures

Substance use was measured by asking the subjectswhether they currently use tobacco or alcohol, and thefrequency of use. Furthermore, the number of cigarettes

Table 1 Selected characteristics of students participating in the‘Healthy School and Drugs’ project and in control subjects at M0.

Proportion

GenderFemale 50.9Male 49.1

Parental permission to useTobacco 15.7Alcohol 31.2Marijuana 2.2

Discussion with parents about use ofa

Tobacco 66.7Alcohol 60.2Marijuana 56.9

Peer pressure to useb

Tobacco 17.7Alcohol 13.7Marijuana 3.9

Age M = 12.4 (SD = 0.5)

a Respondents discuss sometimes or often with parents about the use of sub-stance; b proportion of subjects indicating that they experience peer pressureoften or occasionally.

The effects of drug abuse prevention at school 69


and the number of alcoholic drinks per week were measured. For alcohol, the number of alcoholic drinksper occasion was also measured. Marijuana use was measured by asking whether the respondent had everused marijuana. Additionally, it was asked how often therespondent uses marijuana.

Attitude towards tobacco use was measured with sixitems asking for the estimated impact on fitness, health,the feeling of being part of the peer group because ofusing tobacco and whether the subjects think the use willbe enjoyable. The answers were rated on five-point scales.The scores on the five questions were summed up, result-ing in one overall measure of attitude towards tobaccouse (Cronbach’s a: 0.37). Because the reliability coeffi-cient was considered to be too low, this scale was not usedin the analysis comparing the experimental to the controlgroup. The attitude towards alcohol use was measuredwith a five-question scale (Cronbach’s a: 0.66), and the attitude towards marijuana use with another five-question scale (Cronbach’s a: 0.76). The reliability coefficients of these scales were considered satisfactory.

Knowledge about tobacco was measured with four

basic questions on the health effects of tobacco use(three-point scales). The scores were summed, resultingin one overall measure of knowledge on tobacco. A scaleconstructed from six more questions estimated theknowledge on health effects of alcohol use, and a scaleconstructed from three questions measured the knowl-edge on the health effects of marijuana use.

Self-efficacy for smoking was measured with threeitems assessing the estimated success of not smoking indifferent social situations (being at a party; being teasedby friends for not smoking; a friend insists on smoking).The scores on the three-point items are summed up,resulting in one scale assessing self-efficacy for notsmoking (Cronbach’s a: 0.75). Self-efficacy for alcoholuse and for marijuana use were measured with twoscales, each constructed from three more questions(Cronbach’s a: 0.81; 0.88).

Intervention

The ‘Healthy School and Drugs’ project is a multi-component, school-based prevention programme for

Table 2 Substance use in students participating in the ‘Healthy School and Drugs’ project and in control subjects, before the intervention,1 year later, 2 years later and 3 years later.

Group M0 M1 M2 M3

N E a 1156 1095 1009 783b

C 774 740 660 622

TobaccoProportion users E 0.055 0.092* 0.224† 0.311 NS

C 0.059 0.131 0.263 0.336Proportion daily usec E 0.187 0.239 NS 0.387 NS 0.506*

C 0.067 0.155 0.384 0.507Cigarettes/week (M; SD) E 12.07 (20.27) 12.99 (26.21) NS 20.75 (26.90) NS 28.41 (31.33) NS

C 7.02 (13.13) 9.42 (15.51) 20.43 (29.96) 29.72 (31.90)

AlcoholProportion users E 0.269 0.328** 0.566*** 0.738***

C 0.318 0.428 0.654 0.805Proportion weekly usersc E 0.120 0.157 NS 0.306 NS 0.442*

C 0.130 0.188 0.335 0.569Drinks/week (M; SD) E 0.58 (1.57) 0.94 (2.06) NS 2.01 (4.16) NS 4.06 (7.20)**

C 0.53 (2.08) 0.87 (1.61) 2.52 (4.92) 5.27 (7.57)Drinks/occasion (M; SD) E 1.89 (2.06) 1.96 (2.14)** 3.27 (3.47) NS 4.79 (4.30)***

C 1.71 (1.26) 2.10 (2.25) 3.60 (3.82) 5.82 (5.78)

MarijuanaProportion users E – d 0.025e 0.071* 0.165 NS

C – 0.024 0.112 0.185Proportion monthly usersc E – d 0.395 0.549 0.585*

C – 0.190 0.576 0.508

† p < 0.1; * p < 0.05; ** p < 0.01; *** p < 0.001.a E = experimental group; C = control group. b The large decline of respondents was caused by the exclusion of one of the experimental schools. c Proportionof those who use substance (analyses are conducted with overall frequency). d Cannabis use was not measured at M0; the measure for cannabis at M1 was usedas pretest for the measurement at M2 and M3.



high school students of 12–18 years. The theoreticalframework for the ‘Healthy School and Drugs’ projectwas based on the theory of planned behaviour (Ajzen &Fishbein 1990), Bandura’s social cognitive theory(Bandura 1996) and McGuire’s model of behaviouralchange (McGuire 1985). These models were adapted intothe ‘ASE’ model (De Vries 1992) that explains intentionand behaviour by distinguishing three main determi-nants: attitude (a person’s judgment of possible behav-iour), social influence (composed of opinions andexpectations others have towards the behaviour) and self-efficacy (a person’s confidence in succeeding inaccomplishing a certain behaviour).

The ‘Healthy School and Drugs’ consists of five majorcomponents, which are adopted and implemented over a 3 year period at each participating school. The first step which has to be taken at each participating school is a coordinating committee, consisting of school staff(teachers, managers, and directors), a health official(from the health education department of the municipalhealth service) and a parents’ representative. This com-mittee coordinates all activities on substance use preven-tion at school, and draws up a working plan each year.

The second component of the ‘Healthy School andDrugs’ is a series of educational lessons for junior–secondary education (12–15 years). This series consistsof three lessons about tobacco in the first year, threelessons about alcohol in the first or second year (depend-ing on the preferences of the teacher) and another threelessons in the second or third year about marijuana,ecstasy and gambling. These lessons are the core of the‘Healthy School and Drugs’. It is stressed in all the mate-rial that warning about the dangers of drugs has noeffects on drug abuse, and that information alone is notenough to prevent students from using drugs. The‘Healthy School and Drugs’ uses an approach in whichinformation, development of a healthy attitude towardsdrugs and the training of refusal skills are basic elements.In each first lesson of the three series, basic informationabout the substance is given. The second and thirdlessons concentrate on attitude and behaviour. Theselessons contain skills training in making choices, refusalskills and increasing self-esteem. Many materials havebeen developed to support teachers in their work, includ-ing manuals for all series of lessons, video tapes, age-specific exercises, and brochures for students.

The third component consists of the formulation ofschool regulations on drug use, for example on the use of alcohol and tobacco at school and at school parties. Amanual for developing regulations or adapting existingregulations is available from the local health official.

The fourth component is the development of a systemof early detection of students with drug problems, andsupport and counselling for these students. Schools are

supported by training teachers and counsellors in earlydetection of drug abuse and counselling. The supportinghealth officials are available to help schools decidewhether referral to specialized services is necessary.

The fifth component is involving parents in drugabuse prevention at school. Several methods are avail-able, including manuals for a parents’ evening,brochures for parents and examples of newsletters.

Analyses

Since we used a quasi-experimental design, we examinedwhether we needed to control for confounding variablescaused by differences between experimental and controlsubjects at pretest. We conducted a series of multiple and logistic regression analyses to identify differencesbetween experimental and control group at pretest ondemographic and on all individual items from theoutcome variables (p < 0.05). We found the proportion of subjects who smoked tobacco to be larger in the experimental group than in the control group at M0.Furthermore, we found four items of the scales measur-ing smoking-attitudes and alcohol self-efficacy to be different in the experimental and control group. More-over, the overall knowledge with respect to marijuana usewas found to be higher in the control group.

The resulting variables were included as predictors inthe multiple and logistic regression analyses that wereused to test whether differences between experimentaland control group on outcome variables are due to theintervention or not. None of these variables was found to be significantly (p < 0.05) related to the dependentvariables.

RESULTS

Effects on substance use

As was expected for this age group, the proportion ofstudents using tobacco, alcohol or cannabis increasedconsiderably during the study. The results indicated sig-nificant effects of the intervention on measures of sub-stance use at M1 (tobacco and alcohol use), at M2 (alcoholand cannabis), and at M3 (alcohol use) (Table 2).

Furthermore, significant effects of the interventionwere found on frequency of smoking at M3 (p < 0.05); frequency of alcohol use at M3 (p < 0.01); the number of alcoholic drinks per week at M3 (p < 0.01); and thenumber of alcoholic drinks per instance (at M1 and M3 p< 0.001). The proportion students who used marijuanawas significantly lower in the experimental group than inthe control group at M2. The difference between experi-mental and control group in marijuana use was no



longer significant at M3. Unexpectedly, students in theexperimental group use marijuana more frequently thanin the control group at M3.

Knowledge, attitudes and self-efficacy

Significant effects were found on knowledge about sub-stances. This was true for knowledge on tobacco, alcoholand marijuana at M3, for tobacco and alcohol at M2 andfor tobacco at M1. No effects of the intervention werefound on self-efficacy towards the use of tobacco. A significant effect of the intervention on the attitudetowards alcohol use was found at M2, but not at M1 andM3. A significant effect on self-efficacy towards alcoholwas found at M1, but not at M2 and M3. Attitude towardsthe use of cannabis differed for experimental and controlgroups only at M3, but not at M1 and M2. No effects werefound on self-efficacy towards cannabis use (Table 3).

DISCUSSION

This study had several limitations. Firstly, subjects werenot assigned randomly to experimental or comparisonconditions. Although a thorough examination of pos-sible confounding variables was conducted, the risk thatmajor confounding variables were not measured remainsan open question. Secondly, substance use was only

measured with self-report questionnaires. Subjects in theexperimental condition may have been more inclined toreport using less drugs than they actually did. Thirdly, itwas not examined whether the intervention was con-ducted by the teachers as was described in the protocol.Because of these limitations the results of this studyshould be considered with caution.

On the other hand, we did find encouraging results.The ‘Healthy School and Drugs’ projects seem to result inimportant effects on substance use, especially on alcoholuse. Between 12 and 15 years, many adolescents startexperimenting with tobacco, alcohol and other drugs.The ‘Healthy School and Drugs’ project may reduce thenumber of adolescents who start experimenting. Therewere effects on tobacco use, but they decrease over timeand had disappeared at the end of the interventionperiod.

Unexpectedly, the intervention seemed to result in asomewhat more frequent use of marijuana among thosewho use it. This has been found in other research amongDutch students (De Haes & Schuurman 1975). In thisearlier research it was found that this increase in fre-quency was only a temporary effect. Nevertheless, thismay be a negative effect of the ‘Healthy School andDrugs’ project, which should be examined in more detailin future research.

The intervention was found to have positive effects onknowledge with respect to substance use. Most health

Table 3 Knowledge about substances, attitudes towards substances and self-efficacy towards substance use in students participating in the‘Healthy School and Drugs’ project and in control subjects, before the intervention, 1 year later, 2 years later and 3 years later.

Group M0 M1 M2 M3

TobaccoKnowledge Ea 1.13 (1.04) 2.33 (1.03)*** 2.49 (0.92)*** 2.63 (0.95)**

C 1.30 (1.07) 1.76 (0.99) 2.14 (1.05) 2.21 (1.00)Self-efficacy E 5.95 (2.73) 5.67 (2.69) NS 5.66 (2.73) NS 5.73 (3.02) NS

C 5.83 (2.69) 5.65 (2.65) 5.77 (2.87) 5.57 (2.94)Alcohol

Knowledge E 2.35 (1.43) 2.68 (1.37) NS 3.81 (1.30)*** 4.12 (1.23)***C 2.34 (1.35) 2.69 (1.31) 3.31 (1.36) 3.68 (1.31)

Attitude E 11.67 (3.89) 11.59 (4.01) NS 12.18 (3.89)* 12.74 (3.78) NSC 11.63 (3.76) 11.71 (3.68) 12.66 (3.93) 13.09 (3.68)

Self-efficacy E 6.30 (2.91) 6.10 (3.04)* 6.44 (3.23) NS 6.57 (3.37) NSC 6.33 (2.83) 6.32 (2.93) 6.66 (3.33) 6.58 (3.50)

MarijuanaKnowledge E – 0.82 (0.79)b 1.11 (0.80) NS 1.30 (0.79)***

C – 0.94 (0.83) 1.00 (0.82) 1.12 (0.81)Attitude E – 12.54 (4.58) 12.00 (4.23) NS 11.40 (4.06)*

C – 12.68 (4.20) 12.57 (4.36) 12.05 (4.14)Self-efficacy E – 4.54 (2.54) 4.73 (2.77) NS 4.71 (2.75) NS

C – 4.64 (2.58) 4.80 (2.95) 4.67 (2.93)

* p < 0.05; **p < 0.01; ***p < 0.001a E = experimental group; C = control group. b Cannabis use was not measured at M0; the measure for cannabis at M1 was used as pretest for the measure-ment at M2 and M3.



professionals do consider this to be an important result ofschool-based drug prevention programmes. Sufficientknowledge about substances and health consequences of substance use indicates that adolescents at least areaware of the dangers they encounter when they use.

It is remarkable that only few effects of the projectwere found on attitude towards substance use and onself-efficacy. In most other studies on school-based drugprevention programmes, significant effects are found onattitude (Tobler et al. 2000). We do not have an adequateexplanation for this finding. Possibly, the interventiondoes not focus sufficiently on these aspects. However,despite the lack of effects on attitude, effects are found onsubstance use.

The most interesting aspect of the ‘Healthy Schooland Drugs’ project is the high dissemination rate ofthe project in about 70% of the Dutch schools. The dis-semination has been a major point of interest during the development of the programme. The disseminationstructure of ‘The Healthy School and Drugs’ has beenorganized at three levels. The basic level is the school, inwhich all activities are organized, with the coordinatingcommittee as the stimulating force. The second level isthe support to the school provided by the local healtheducation department of the municipal health service. Inthe Netherlands, municipalities and their health servicesare responsible for the implementation of collective prevention measures concerning health risks for youngpeople. These health services traditionally have a closerelationship with schools (e.g. dental care, vaccination).These local services approach the schools and encouragethem to participate in the project. Because they haveclose working relations with the schools in many areas,this is a crucial factor for successful dissemination. Thenthey support participating schools in the organizationand realization of the project. The third level of the dis-semination structure of ‘The Healthy School and Drugs’takes place at national level. The Trimbos Institute(Netherlands Institute of Mental Health and Addiction)coordinates the project at national level. All materials aredeveloped in close cooperation with local health educa-tion specialists, teachers and students, and are distrib-uted to the municipal health services and to schools.Several specialized training courses are held regularly for the health educators and school staff. This tripartitedissemination structure has resulted in the high level ofacceptance of the ‘Healthy School and Drugs’ project byschools.

This study shows that it is not only possible to developdrug prevention programmes that have some effect, butalso to develop programmes that are accepted widely bylocal schools. The impact of a programme can be seen asthe product of the effects and the level of dissemination.Although the effects of the ‘Healthy School and Drugs’

project may be more moderate than the effects of veryintensive drug prevention programmes that have beendeveloped at university settings, there is no doubt that itsimpact can be much larger. Although most effects of theproject were positive, a word of caution is needed for the negative effect we found on marijuana use. Negativeeffects of school prevention programmes are not verycommon, and future research is clearly necessary.

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The effects of drug abuse prevention at school: the ‘Healthy School and Drugs’ project