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Prevention interventions for community members

This page refers to the current evidence on the effectiveness of the available prevention interventions for communities. Information on the methodology used and the definition of terms can be found on the methodology page.

Date of last update: 05.2017 Next update: 10.2017

Available evidence for prevention interventions on communities

Beneficial

Comprehensive community-based programmes targeting high-risk youth

Comprehensive approaches involving community, school and family were found effective in a systematic review of 222 studies (14 systematic reviews; 103 RCTs; 52 Controlled non-randomized studies; 18 CBA; 35 BA) (Jones et al., 2006) at preventing/delaying/reducing:

all substances when compared with community-only programmes and school-community programmes targeting high-risk youth (SMD = 0.38 and 0.36 respectively), and in high-risk individuals when compared with low-risk individuals (SMD = 0.42 and 0.08);
tobacco when compared with community-only programmes and school-community programmes targeting high-risk youth (SMD = 0.46 and 0.48), and in high-risk individuals when compared with low-risk individuals (SMD = 0.49 and 0.03);
alcohol when compared with community-only programmes and school-community programmes targeting high-risk youth (SMD = 0.49 and 0.49), and in high-risk individuals when compared with low-risk individuals (SMD = 0.56 and 0.05);
cannabis when compared with community-only programmes and school-community programmes targeting high-risk youth (SMD = 0.82 and 0.79), and in high-risk individuals when compared with low-risk individuals (SMD = 0.84 and 0.22);
all illicit drugs when compared with community-only programmes and school-community programmes targeting high-risk youth (SMD = 0.56 and 0.54), and in high-risk individuals when compared with low-risk individuals (SMD = 0.65 and 0.05).

There was no difference in effectiveness between ‘school-community’ programmes and ‘community-only’ programmes. Moreover, low risk population effect sizes were significantly greater across all types of interventions (‘comprehensive’, ‘school-community’, ‘community-only’) for tobacco (SMD = 0.05, SMD = 0.13); and cannabis (SMD = 0.04, SMD = 0.10). No other significant differences were reported.

Mentoring for preventing alcohol use in young people

Mentoring (intended as a supportive relationship in which one person offers support, guidance and concrete assistance to the partner, based on the sharing of experience and expertise without expectation of personal gain by the mentor - Center for Substance Abuse Prevention 2000) was found in a systematic review (Thomas et al., 2011) more effective than no interventions in:

preventing alcohol use (3 RCTs) (RR 0.71, 95% CI 0.57 to 0.90, p = 0.005).

Street-level drug policing to reduce drug offences and drug-related calls for service

Street-level law enforcement approaches (including community-wide policing, problem-oriented policing, hot spots policing and standard model of policing) were found in a systematic review (EMCDDA 2017 - not published, based on Mazerolle et al., 2007) to be effective in:

reducing drug offences (OR 1.53, 95% CI 0.75 to 3.13)
- problem-oriented policing (OR 2.44, 95% CI 1.30 to 4.60)
- community-wide policing (OR 1.85, 95% CI 1.53 to 2.22)
reducing drug-related calls for service (OR 1.33, 95% CI 1.07 to 1.65)
- problem-oriented policing (OR 1.44, 95% CI 1.16 to 1.77)

Likely to be beneficial

Anti-tobacco multi-component community interventions

Coordinated, widespread, multi-component community interventions include age restrictions on tobacco purchase, programs for prevention of disease (like heart disease), mass media and school programs. Such interventions were found in a systematic review of 17 studies (Sowden and Stead, 2003) to:

reduce smoking prevalence when compared to no intervention control and to school-based programmes only;
reduce the rate of increase in smoking prevalence when compared to mass-media campaign alone.

Communities That Care (CTC) approach to prevent use and reduce youth problematic behaviours

The Communities That Care (CTC) approach (i.e. community coalitions that develop a common strategy and mobilise communities in prevention and health promotion initiatives) was found in a systematic review (EMCDDA 2017, studies = 5) to be effective in:

reducing substance use and delinquency behaviours (USA trials)

Computer-based interventions to reduce recreational drug use

Computer-based interventions targeting specifically recreational drug users were found in a systematic review (Wood et al., 2014) to have general positive results in:

reducing use of drugs both immediately and in the mid-term when targeting specifically recreational drug users

Interactive programmes targeting vulnerable youth

Programmes offering strong behavioural life skills development content, emphasised team-building, interpersonal communication methods, and introspective learning approaches focusing on self-reflection were found to be effective in a review of studies (Springer et al., 2004) in:

reducing 30-day tobacco, alcohol and herbal cannabis (‘marijuana’) use among vulnerable youth.

These programmes were based upon a clearly articulated and coherent programme theory, and provided quality contact with young people.

Multi-component prevention programs for alcohol misuse in young people

Multi-component prevention programs (intervention delivered in more than one setting) have shown in a systematic review (Foxcroft et al., 2011) of 20 RCTs to be effective in:

reducing alcohol misuse in adolescents (12 of the 20 trials showed some evidence of effectiveness).

Support groups combined with peer mentor training delivered to young people with parents or other family members who are substance users

There is evidence from a narrative review including results of one RCT (N=271) (Faggiano 2008) that such interventions in the short to medium term can be effective at improving young people’s:

program knowledge (z = 7.03, p < 0.01)
emotion-focused coping (z = 3.67, p < 0.01)
social-support coping (z = 2.20; p < 0.05)
tension-reduction expectancy (z = 2.26; p < 0.05)

Trade-off between benefits and harms

No interventions met the criteria for this category.

Unknown effectiveness

Anti-alcohol/cannabis community interventions

Anti-alcohol/cannabis community interventions were analyzed in a review of 29 reviews (McGrath et al., 2006) and weak studies due to lack of control groups suggested a reduction in:

alcohol use;
cannabis use.

Mentoring for preventing drug use in young people

No pooled analysis could be done on mentoring (understood here to mean a supportive relationship in which one person offers support, guidance and concrete assistance to the partner, based on the sharing of experience and expertise without expectation of personal gain by the mentor — Center for Substance Abuse Prevention 2000) in a systematic review (Thomas et al., 2011) for:

preventing drug use.

Multi-component versus single components programs for alcohol misuse in young people

There is little evidence that interventions with multiple components are more effective than interventions with single components as shown in a systematic review (Foxcroft et al., 2011):

only 1 of the 7 trials where assessment of the additional benefit of multiple versus single component interventions was possible, clearly showed a benefit of components delivered in more than one setting.

Positive youth development (PYD) interventions to reduce substance use

Positive youth development (PYD) interventions i.e. programmes that favour the promotion of positive assets were found in a systematic review with meta-analysis (Melendez-Torres et al., 2016, 10 studies) to have no significant effect in:

reducing substance use

Primary care behavioural interventions to prevent or reduce substance use in children and adolescents

Behavioural interventions (including universal screening, brief interventions and referral to treatment) implemented in primary care settings and targeting youth not seeking or identified as needing special treatment were found in a systematic review without meta-analysis (Patnode et al., 2014) to have no significant effect in:

preventing or reducing illicit drug use (6 studies)

Evidence of ineffectiveness

No interventions met the criteria for this category.

References and definitions

List of references

Explanation of terms used

Below you can find definitions and further explanation for some of the terms used in this section of the Best practice portal. A more general glossary for the best practice portal is also available.

Affective-focused prevention intervention

A type of prevention intervention which aims to they aim to modify inner qualities (personality traits such as self-esteem and self-efficacy, and motivational aspects such as the intention to use drugs).

BA

Before-after (BA) study design

BAL

Blood alcohol level (BAL)

Beneficial

Interventions for which precise measures of the effects in favour of the type of intervention were found in systematic reviews of relevant studies. An intervention ranked as ‘beneficial’ is suitable for most patients/contexts. See the relevant module methodology page for further information.

CBA

Controlled before-after (CBA) study design. UCBA stands for Uncontrolled before-after study design.

CBT

Cognitive behavioral therapy is an individual based intervention occurring in three stages. Phase 1 is aimed at determining and prioritizing the patient’s problems and constructing the treatment contract. Phase 2 is aimed at increasing coping competence and reducing risky behaviors. Phase 3 focuses on relapse prevention. Each session is administered once per week over a period of 4-6 months with 60- to 90-minute sessions (Beck AT, Wright FW, Newman CF, Liese B. Cognitive Therapy of substance abuse. New York: Guilford Press, 1993).

CCT

Controlled clinical trials (CCT)

Cohort study

A cohort study is a type of observational study that follows a group of people (i.e. a cohort) over time. In a prospective cohort study, the cohort is formed and then followed over time. In a retrospective cohort study, data is gathered for a cohort that was formed sometime in the past.

Confidence Interval (CI)

The Confidence Interval (CI) is a measure of the precision (or uncertainty) of study results. It is the interval that most likely includes the true value of the parameter we are calculating, where 'most likely' is taken by common usage to be a 95% probability. Thus the current expression of '95 % CI'. A wide CI indicates less precise estimates of effect and vice versa.

Practical interpretation

If the RR (the relative risk) = 1, or the CI (the confidence interval) = 1, then there is no significant difference between treatment and control groups
If the RR > 1, and the CI does not include 1, events are significantly more likely in the treatment than the control group
If the RR < 1, and the CI does not include 1, events are significantly less likely in the treatment than the control group

CPS

Current population survey (CPS)

Cross-sectional study

A cross-sectional study is a study employing a single point of data collection for each participant or system being studied.They are usually conducted to estimate the prevalence of the outcome of interest for a given population at a given point in time.

Evidence of ineffectiveness

Interventions that gave negative results if compared with a standard intervention or no intervention, for example. See the relevant module methodology page for further information.

Additional information for prevention
For ethical reasons this category in prevention should be considered as interventions with negative and undesired (iatrogenic) effect.

IP

Individual psychotherapy is a standard individual treatment based on counseling and motivational interviewing and focused on substance use triggers and strategies for relapse prevention. It includes elements of cognitive-behavioral therapy (CBT).

IQR

Interquartile range (IQR) - also called the midspread or middle fifty - is a measure of statistical dispersion. It is a trimmed estimator, defined as the 25% trimmed mid-range, and is the most significant basic robust measure of scale.

ITS

Intermittent time series design (ITS)

Knowledge-focused prevention intervention

A type of prevention intervention which aims to to enhance knowledge of drugs, and drug effects, and consequences.

Likely to be beneficial

Interventions that were shown to have limited measures of effect, that are likely to be effective but for which evidence is limited. An intervention ranked as ‘likely to be beneficial’ is suitable for most contexts/patients, with some discretion. See the relevant module methodology page for further information.

Number Needed to Treat (NNT)

The Number Needed to Treat (NNT)indicates the number of patients that needs to be treated to obtain one respondent patient. Numerically the NNT is the reciprocal of the difference between the proportion of events in the experimental and the comparison group (absolute risk reduction). Taking into consideration that the ideal NNT would be 1 (the unreal situation in which every single patient succeeded) it is easily understood that a NNT value close to 3 or 4 would be very good.

Adjusted Odds Ratio (AOR)

The Adjusted Odds Ratio is a way of comparing whether the probability of a certain event is the same between two groups, yet they are calculated adjusting for or controlling for other possible contributions from other variables (tipically demographic variables) in the model. An AOR equal to 1 implies that the the event is equally probable in both groups. An AOR greater than 1 implies that the event is more likely in the first group. An AOR less than 1 implies that the event is less likely in the first group.

Odds Ratio (OR)

The Odds Ratio is a way of comparing whether the probability of a certain event is the same between two groups. Like the Relative Risk, an OR equal to 1 implies that the the event is equally probable in both groups. A OR greater than 1 implies that the event is more likely in the first group. A OR less than 1 implies that the event is less likely in the first group. In medical research, the odds ratio is commonly used for case-control studies, as odds, but not probabilities, are usually estimated. Relative risk is used in randomized controlled trials and cohort studies.

p value

A p-value is a measure of how much evidence we have against the null hypothesis. The null hypothesis represents the hypothesis of no change or no effect. The smaller the p-value, the more evidence we have against the null hypothesis thus it is more likely that our sample result is true. Traditionally, researchers will reject a null hypothesis if the p-value is less than 0.05.

RBS

Responsible beverage service (RBS)

RCT

Randomised controlled trial (RCT)

Relative Risk (RR)

The Relative Risk (RR) is used to compare the risk in the two different groups of people, i.e. treated and control groups to see if belonging to one group or another increases or decreases the risk of developing certain outcomes. This measure of effect will tell us the number of times an outcome is more likely (RR > 1) or less likely (RR < 1) to happen in the treatment group compared with the control group.

Practical interpretation

If the RR (the relative risk) = 1, or the CI (the confidence interval) = 1, then there is no significant difference between treatment and control groups
If the RR > 1, and the CI does not include 1, events are significantly more likely in the treatment than the control group
If the RR < 1, and the CI does not include 1, events are significantly less likely in the treatment than the control group

Trade-off between benefits and harms

Interventions that obtained measures of effects in favour of the intervention, but that showed some limitations or unintended effects that need to be assessed before providing them. See the relevant module methodology page for further information.

Unknown effectiveness

Interventions for which there are not enough studies or where available studies are of low quality (with few patients or with uncertain methodological rigour), making it difficult to assess if they are effective or not. Interventions for which more research should be undertaken are also grouped in this category.

Additional information for prevention
For prevention interventions, this is also known as 'zero effect'.

Skill-focused prevention intervention

A type of prevention intervention which aims to enhance students’ abilities in generic skills, refusal skills and safety skills.

Standardised Mean Difference (SMD)

The Standardised Mean Difference (SMD) is the difference in means divided by a standard deviation. Note that it is not the standard error of the difference in means (a common confusion). The standardized mean difference has the important property that its value does not depend on the measurement scale. It may be useful if there are several trials assessing the same outcome, but using different scales.

z score (Standard Score): The z-score (aka, a standard score) indicates how many standard deviations an element is from the mean of the population.

Case definition

Though there is no single definition for the term 'community', as used here it is understood to mean a group of individuals sharing a common geographical and administrative setting. Interventions within a community do not necessarily address all members of that community but possibly only a specific part, i.e. those at higher risk of substance use (aka vulnerable groups). In cases where the term 'community' is being used in a different sense, this is indicated.

Risk

As for the module on school interventions, being the community a wide concept including many different people and their relations, no specific risks exist in being member of a community. Community based interventions are rather developed with the aim of involving different social structures and actors into comprehensive approaches.

Interventions

Interventions included in this section involve all individuals or specific vulnerable groups in the community and aim to hinder or limit the use of substances.
Also interventions with family- or school-based components were included in this section, provided the community-based component was predominant.

Outcomes

The main aim of prevention interventions provided to communities is to deter or to delay the onset of substance use/abuse by providing all individuals with the information and skills necessary to prevent the problem.

Primary outcomes

Reduction of substance use
Reduction of risky behaviour
Reduction of intention to use
Increase in awareness

References

EMCDDA (2008), Drugs and vulnerable groups of young people, EMCDDA, Lisbon

About the EMCDDA

The European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) is the reference point on drugs and drug addiction information in Europe. Inaugurated in Lisbon in 1995, it is one of the EU's decentralised agencies. Read more >>