The effectiveness of primary interventions to prevent the use of tobacco, alcohol and other drugs among children and adolescents

Background

Although children and adolescents in Norway generally enjoy good health, health behaviour studies show that there is potential for improvement in several areas, particularly when it comes to their use of tobacco, alcohol and other drugs. The health of children and adolescents is important not only in terms of how they experience their childhood but also with respect to their development and health in adulthood. The prevention of poor health habits among children and adolescents has the potential to provide better health throughout the life span. In order to be better able to initiate preventive interventions, it is important to get an overview of the effectiveness of such initiatives, for example when it comes to the use of tobacco and alcohol.

Objective

We aimed to ascertain the effectiveness of primary preventive interventions on health behaviors in children and adolescents with regard to the use of tobacco, alcohol and other drugs.

Method

We completed an overview of systematic reviews in accordance with the Norwegian Knowledge Centre for the Health Services’ handbook. We searched for systematic reviews in 13 international databases. The search was completed in January 2012. Two people independently screened first all titles and abstracts and next all potentially relevant reviews in full text. All systematic reviews of high methodological quality that dealt with preventive interventions concerning tobacco, alcohol or other drugs were included. From the included systematic reviews, we extracted all relevant results, summarized these in text and created tables when deemed appropriate. The quality of the documentation for each main outcome in each systematic review was assessed using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation).

Results

We included ten systematic reviews of high methodological quality. These were published between 2007 and 2011. Eight were Cochrane reviews. Four of the included systematic reviews examined the effectiveness of various preventive interventions on smoking and two dealt with the prevention of alcohol abuse. The last four reviews concerned the effectiveness of various preventive interventions on the use of various drugs.

Smoking: Four systematic reviews dealt with the effectiveness of interventions to prevent smoking by children and adolescents. The results varied: It is uncertain whether community-based programmes are effective (very low quality of evidence); mass media campaigns and school-based interventions may possibly be effective (low quality of evidence); family-based interventions are possibly not effective in keeping children and adolescents smoke-free (moderate quality of evidence).

Alcohol abuse: Two systematic reviews concerned the effectiveness of interventions to prevent alcohol abuse among children and adolescents. The systematic review on the effectiveness of family-based interventions showed that most RCTs (randomized controlled trials) (7 of 9) found a significant difference in the use of alcohol favouring the intervention (2 of 9 found no significant difference). Also the systematic review on the effectiveness of multi-component programs showed that most RCTs (7 of 11) found a significant difference in alcohol abuse favouring the multi-component program (4 of 11 found no significant difference). The results indicated that both family-based- and multi-component programs to prevent alcohol abuse may possibly prevent alcohol abuse among children and adolescents (low quality of evidence).

Various drugs: Four systematic reviews dealt with the effectiveness of various preventive interventions on the use of a variety of drugs. The first systematic review concerned the effectiveness of school-based interventions to prevent the use of illegal drugs. Meta-analysis results indicated that interventions emphasizing skills may lead to significant less use of hard drugs compared to usual practice (moderate quality of evidence). The second systematic review concerned drug prevention interventions in non-school settings (categorized as family oriented or multi-component). There were conflicting results and the quality of the evidence was very low. Thus, it is uncertain whether drug prevention interventions in non-school settings lead to significant differences in the use of marijuana compared to no or active programs. The third systematic review concerned the effectiveness of school-based interventions to prevent the use of alcohol and marijuana among 10-15 year olds. School-based interventions that emphasize knowledge are possibly not effective in preventing alcohol use compared with no program (moderate quality of evidence). However, comprehensive school-based interventions to prevent the use of alcohol and marijuana lead to significantly less use of both alcohol and marijuana compared to no program (high quality of evidence). The fourth and final systematic review concerned the effectiveness of parenting programs to prevent the use of tobacco, alcohol and other drugs.

The results varied: Parenting programs may possibly prevent i) smoking in children ca 5-11 years, compared to no program, ii) use of alcohol or other drugs in children and adolescents ca 11-14 years, compared to various controls (low quality of evidence). It is uncertain whether parenting programs prevent i) use of alcohol in adolescents ca 11-14 years, ii) use of various drugs in adolescents ca 14-18 years, compared to various controls (very low quality of evidence).

Discussion

The evidence base in this review of systematic reviews is comprehensive and the results vary in strength. The quality of the evidence in the ten included systematic reviews ranged from very low to high. In most cases, the documentation was down-graded because the included studies were small, the results were inconsistent, and there were methodological study flaws.

Conclusion

The ten included systematic reviews showed that:

• Comprehensive school-based interventions to prevent the use of alcohol and marijuana are effective in preventing the use of both alcohol and marijuana among 10-15 year olds.
• School-based interventions, which emphasize skills, to prevent the use of illegal drugs may be effective in preventing the use of hard drugs among children and adolescents.
• The following interventions to prevent smoking may possibly be effective: i) mass-media campaigns, ii) school-based interventions that emphasize social skills, iii) parent-based interventions for children aged 5-11 years.
• The following prevention interventions may possibly be effective: i) school-based interventions against illegal drugs which emphasize knowledge to prevent use of marijuana, ii) parent-based interventions to prevent the use of tobacco, alcohol, and other drugs among adolescents aged 11-14 years, iii) family-based interventions to prevent alcohol abuse among children and adolescents, iv) multi-component interventions to prevent alcohol abuse among children and adolescents.
• School-based interventions, which emphasize knowledge, to prevent the use of alcohol and marijuana may not be effective in preventing alcohol abuse among adolescents aged 10-15 years.
• Family-based interventions to prevent smoking among children and adolescents may not be effective in keeping children and adolescents smoke free.
• The documentation was too limited to draw any conclusions regarding the effectiveness of a range of other drug prevention interventions.

Future research should focus on the long-term effectiveness of substance abuse prevention interventions with follow-up at least half a year, preferably longer, post project completion. There is also a need for high-quality studies concerning the effectiveness of community-based interventions to prevent smoking, non-school-based interventions to prevent the use of marijuana as well as parenting programs to prevent the use of tobacco, alcohol, and other drugs among children and adolescents.