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Best practice portal:
Prevention interventions for the general population

This page refers to the current evidence on the effectiveness of the available prevention interventions for the general population. 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

Prevention interventions in the general population

Summary: Mass-media campaigns associated with other interventions proved effective in reducing licit drugs. On the other hand, mass-media campaigns as stand alone interventions were considered ineffective for reducing licit and illicit drugs.

Beneficial

No interventions met the criteria for this category.

Likely to be beneficial

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 in the mid-term (up to 6 months) in universal drug prevention programmes

Mass media campaigns to reduce drink driving and traffic accidents

Mass media campaigns to reduce drink driving, were found to be effective in a narrative review (Wakefield, 2010) of 4 studies (considering various mass media campaigns).

Trade-off between benefits and harms

No interventions met the criteria for this category.

Unknown effectiveness

Alcohol drinking education guidelines

No assessments have been conducted of whether the publicising of alcohol drinking guidelines affects alcohol-related harm, according to a narrative review (Anderson 2009).

Media campaigns for the prevention of illicit drug use in young people

Mass-media campaigns in combination with school-based, community-based or national programmes were found in a systematic review (Ferri et al., 2013, 23 studies, N= 188 934) to have no statistically significant different effect in:

  • reducing substance use
    • pooled results of 5 RCTs (N = 5470) show no effect of media campaign intervention (standardised mean difference (SMD) -0.02; 95% confidence interval (CI) -0.15 to 0.12)
    • pooled results of 4 out of 5 ITS studies (N = 26 405) focusing on methamphetamine use showed a reduction only in past-year prevalence of methamphetamine use among 12 to 17 years old
    • a further 5 studies (N = 151 508), which could not be included in meta-analyses, reported a drug use outcome with varied results including a clear iatrogenic effect in one case)

Anti-tobacco mass-media campaigns in combination with other components

Mass-media campaign in combination with school-based, community-based or national programmes were found in a systematic review (Carson et al., 2017, 8 studies, N= 17 385) to be inconclusive regarding:

  • reduced smoking behaviour of young people (3 studies (n = 17,385) found some evidence but the remaining 5 studies (n = 72,740) did not detect a significant effect on smoking behaviour)

Evidence of ineffectiveness

Standalone mass-media campaigns for alcohol consumption

Overall, standalone mass-media campaigns for alcohol consumption were found to be ineffective in a narrative review (Wakefield 2010) based on the following outcomes:

  • warnings on drinks bottles, as a standalone measure have no effect on alcohol consumption. Campaigns to lessen alcohol intake have had little success. Most have been targeted towards young people but the potential effects have generally been overshadowed by widespread unrestricted alcohol marketing strategies and the view of drinking as a social norm.
  • safe drinking campaigns sponsored by alcohol companies have been ineffective in changing drinking behaviour, because the messages are viewed as ambiguous by recipients.

Standalone mass-media campaign for tobacco consumption

Standalone mass-media campaigns (not associated with other components such as school-based, community-based or national programmes) were found to be not effective in reducing tobacco consumption in a  review of reviews of mass-media campaigns (Bühler and Kröger, 2006).

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

It is assumed that all members of the population share the same general risk for substance abuse, although the risk may vary greatly among individuals.

Risk

Individuals do not become involved with substances solely on the basis of personal characteristics. Rather, they are influenced by a complex set of factors in the environment, such as what is considered normal, expected or accepted in the communities in which they live, the rules or regulations and taxes of their countries, the publicity messages to which they are exposed, and the availability of alcohol, tobacco, and illicit drugs. Substance abuse is thus viewed as a product of the overall system.

Interventions

Main strategies are mass media campaigns as well as interventions lsuch as the control of markets or coercive measures (age controls, tobacco bans). These interventions, beyond aspects of coercion and restriction, may also include promotion elements such as providing opportunities, stimuli and encouragement for change. General population strategies predominantly target legal drugs, yet they are important for the whole prevention field because early, widespread and intense use of alcohol and tobacco are related to illicit drug use in many countries.

Outcomes

The main aim of prevention interventions delivered to the general population is to deter or to delay the onset of substance use 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

 

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Page last updated: Tuesday, 18 July 2017