A case study of publication bias in an influential series of reviews of drug education

Alcohol and Brain Development in Adolescents and Young Adults: A Systematic Review of the Literature and Advisory Report of the Health Council of the Netherlands

Young people, whose brains are still developing, might entail a greater vulnerability to the effects of alcohol consumption on brain function and development. A committee of experts of the Health Council of the Netherlands evaluated the state of scientific knowledge regarding the question whether alcohol negatively influences brain development in young people. A systematic literature search for prospective studies was performed in PubMed and PsychINFO, for longitudinal studies of adolescents or young adults ranging between 12 and 24 y of age at baseline, investigating the relation between alcohol use and outcome measures of brain structure and activity, cognitive functioning, educational achievement, or alcohol use disorder (AUD), with measures at baseline and follow-up of the outcome of interest. Data were extracted from original articles and study quality was assessed using the Newcastle-Ottawa Scale. A total of 77 studies were included, 31 of which were of sufficient quality in relation to the study objectives. There were indications that the gray matter of the brain develops abnormally in young people who drink alcohol. In addition, the more often young people drink or the younger they start, the higher the risk of developing AUD later in life. The evidence on white matter volume or quality, brain activity, cognitive function, and educational achievement is still limited or unclear. The committee found indications that alcohol consumption can have a negative effect on brain development in adolescents and young adults and entails a risk of later AUD. The committee therefore considers it a wise choice for adolescents and young adults not to drink alcohol.

Políticas de prevenção ao abuso de drogas no Brasil e nos Estados Unidos

O objetivo deste estudo foi discutir as políticas públicas de prevenção ao abuso de drogas destinadas aos jovens no Brasil e nos Estados Unidos. A formulação dessa política no Brasil tem-se estabelecido a partir de programas que são questionados internacionalmente em termos epistemológicos, teóricos e metodológicos. Conclui-se que a construção de políticas sociais na América Latina permanece atravessada pela manutenção da dependência aos países centrais, uma vez que as tensões entre os modelos proibicionista e de redução de danos se mantêm entre o que preveem as políticas de prevenção ao abuso de drogas da Secretaria Nacional de Políticas sobre Drogas e do Ministério da Saúde e o que de fato é executado. Sugere-se buscar autonomia em relação aos modelos de ações preventivas impostos pelos países dominantes, por meio de um debate mais amplo entre pesquisadores, profissionais, usuários e movimentos sociais para o protagonismo de políticas mais adequadas ao Brasil.

School-based programmes that seem to work

H. Pape: School-based programmes that seem to work: Useful research on substance use prevention or suspicious stories of success?

School-based prevention programmes targeted at adolescent substance use rarely seem to have the desired effects on behaviour. It is true that some outcome studies do conclude that such programmes have been successful, but they are relatively few and far between. Even so, one may ask whether the body of published research in this field may originate from unrealistic optimism due to publication bias and underreporting of no or counterproductive effects. Thus, anecdotal evidence suggests that the literature is biased in favour of studies with positive findings. Moreover, nearly all these studies have been carried out by programme developers, and it is well known that researchers with vested interests are more likely to bring “good news” than independent researchers. Indeed, rather than approaching the field with critical reflection, some evaluators have intended to prove that school-based prevention works and have conducted their research accordingly. Examples of questionable analytical approaches and selective reporting of positive ifindings are consequently not hard to find. The external validity of evaluation studies with favourable outcomes is also often questionable because they almost exclusively have assessed the effects of programmes delivered under optimal rather than real-life conditions. In conclusion, the empirical “evidence” in favour of school-based substance use prevention programmes is generally weak and does not allow recommendation of widespread dissemination of any specific programme.

Prevention of alcohol and drug misuse in adolescents: An overview of systematic reviews

Background

– Systematic reviews have evaluated a wide variety of programmes aiming to prevent, reduce or delay substance use in adolescents. This paper presents an overview of recent systematic reviews, summarising the evidence on the effectiveness of prevention strategies which target adolescents misusing alcohol and/or drugs.

Methods

– We performed a comprehensive search in major electronic databases, consulted websites and checked reference lists of relevant articles. Studies that met our inclusion criteria were critically appraised using the AMSTAR instrument. The findings from the included systematic reviews were synthesised using a vote counting procedure.

Results

– Twenty-one systematic reviews were identified. Ten of these were rated as of high quality. There was little overlap between reviews in terms of the target group, intervention, setting and outcome measures. The components or mechanisms of the prevention programmes were poorly described. Ten reviews evaluated school-based prevention. The effects of these prevention programmes are promising, while effects of community-based, family-based and multi-faceted programmes were less convincing.

Conclusion

– Based on the current evidence, there is a small but consistent positive effect of school-based prevention programmes, but it is less clear what the “active ingredient” is. For example, which group should one target, in which setting and in which circumstances? A set of standardised process and outcome measures would allow us to better compare and statistically pool the results of original studies and reviews. This overview of reviews, like similar other overviews, should encourage researchers to increase uniformity and consistency between studies. This would improve the comparability of evidence, which is needed to formulate valid recommendations for practice.

Parental drinking and adverse outcomes in children: A scoping review of cohort studies

INTRODUCTION AND AIMS

There is a growing interest in measuring alcohol's harms to people other than the drinker themselves. 'Children of alcoholics' and foetal alcohol spectrum disorder have received widespread attention. Less is known about how children are affected by post-natal exposure to parental drinking other than alcohol abuse/dependence. In this scoping review, we aim to assemble and map existing evidence from cohort studies on the consequences of parental alcohol use for children, and to identify limitations and gaps in this literature.

DESIGN AND METHODS

Systematic review methods were used. Electronic databases were searched (1980 to October 2013) and a total of 3215 abstracts were screened, 326 full text papers examined and 99 eligible for inclusion according to selection criteria including separation of exposure and outcome measurement in time and report of a quantitative effect size.

RESULTS

The main finding is the large literature available. Adolescent drinking behaviour was the most common outcome measure and outcomes other than substance use were rarely analysed. In almost two of every three published associations, parental drinking was found to be statistically significantly associated with a child harm outcome measure. Several limitations in the literature are noted regarding its potential to address a possible causal role of parental drinking in children's adverse outcomes.

DISCUSSION AND CONCLUSIONS

This study identifies targets for further study and provides a platform for more targeted analytic investigations which ascertain risk of bias, and which are capable of considering the appropriateness of causal inferences for the observed associations. [Rossow I, Felix L, Keating P, McCambridge J. Parental drinking and adverse outcomes in children: A scoping review of cohort studies. Drug Alcohol Rev 2016;35:397-405].

Does parental drinking influence children's drinking? A systematic review of prospective cohort studies

AIMS

To evaluate evidence of the capacity for causal inference in studies of associations between parental and offspring alcohol consumption in the general population.

METHODS

A systematic search for, and narrative analysis of, prospective cohort studies of the consequences of drinking, except where assessed prenatally only, or with clinically derived instruments. Primary outcome measures were alcohol use or related problems in offspring, which were collected at least 3 years after exposure measures of parental drinking. The systematic review included 21 studies comprising 26,354 families or parent-child dyads with quantitative effect measures available for each study. Criteria for capacity of causal inference included (1) theory-driven approach and analysis; (2) analytical rigour; and (3) minimization of sources of bias.

RESULTS

Four of the 21 included studies filled several, but not all, criteria and were assessed to have some capacity for causal inference. These four studies found some evidence that parental drinking predicted drinking behaviour in adolescent offspring. The remaining 17 studies had little or no such capacity.

CONCLUSIONS

There is a fairly large and consistent literature demonstrating that more parental drinking is associated with more drinking in offspring. Despite this, existing evidence is insufficient to warrant causal inferences at this stage.

Effects of Brief Alcohol Interventions on Drinking and Driving among Youth: A Systematic Review and Meta-analysis

OBJECTIVE

Alcohol-impaired driving persists as a major cause of traffic fatalities and injuries among young drivers. This meta-analysis examined whether brief alcohol interventions were effective in reducing driving after drinking among adolescents and young adults.

METHOD

Our systematic search identified 12 experimental/quasi-experimental evaluations (16 intervention groups) that measured driving while intoxicated and related consequences and provided data for effect size calculation (N = 5,664; M age =17 years; 57% male). The studies were published between 1991 and 2011. Three-level random-effects meta-analyses using a structural equation modeling approach were used to summarize the effects of the interventions.

RESULTS

Compared with controls, participants in brief alcohol interventions reported reduced drinking and driving and related consequences (ḡ = 0.15, 95% CI [0.08, 0.21]). Supplemental analyses indicated that reductions in driving while intoxicated were positively associated with the reduced post-intervention heavy use of alcohol. These findings were not attenuated by study design or implementation factors.

CONCLUSIONS

Brief alcohol interventions under 5 hours of contact may constitute a promising preventive approach targeting drinking and driving among adolescents and young adults. Reducing heavy episodic alcohol consumption appeared to be a major factor in reducing drunk-driving instances. Interpretation of the findings must be made with caution, however, given the possibility of publication bias and the small observed effect size. Future research should focus on the exact mechanisms of behavior change leading to beneficial outcomes of brief alcohol interventions and the potential effectiveness of combined brief interventions and other preventive approaches.

Age of first drinking and adult alcohol problems: systematic review of prospective cohort studies

BACKGROUND

Alcohol policies around the world seek to delay the initiation of drinking. This is partly based on the influential idea that earlier initiation is likely to cause adult alcohol problems. This study synthesises robust evidence for this proposition.

METHODS

Systematic review of prospective cohort studies in which adolescent measurement of age of first drink in general population studies was separated by at least 3 years from adult alcohol outcomes. EMBASE, Medline, PsychINFO and Social Policy and Practice were searched for eligible studies, alongside standard non-database data collection activities. Data were extracted on included study methods and findings. Risk of bias and confounding was assessed for individual studies and a narrative synthesis of findings was performed.

RESULTS

The main finding was the meagre evidence base available. Only five studies were eligible for inclusion in this review. The existence of effects of age of first drink on adult drinking and related problems were supported, but not at all strongly, in some included studies, and not in others. Rigorous control for confounding markedly attenuates or eliminates any observed effects.

CONCLUSIONS

There is no strong evidence that starting drinking earlier leads to adult alcohol problems and more research is needed to address this important question. Policy makers should, therefore, reconsider the justification for delaying initiation as a strategy to address levels of adult alcohol problems in the general population, while also addressing the serious acute harms produced by early drinking.

Interventions to prevent the initiation of injection drug use: a systematic review

BACKGROUND

Injection drug use has been identified as a key source of morbidity and mortality, primarily from overdose and the transmission of blood-borne diseases such as HIV. Experts have therefore called for the prioritization of resources toward the prevention of injection drug use. However, these strategies have not been systematically assessed.

METHODS

PRISMA guidelines were used to systematically review and extract findings from the peer-reviewed literature evaluating the effectiveness of interventions to prevent injecting initiation. We searched 10 English language electronic databases (PubMed, PsycINFO, EMBASE, Cochrane CENTRAL, CINAHL, Web of Science, TOXNET, AIDSLINE, AMED and ERIC), the Internet (Google, Google Scholar), and article reference lists, from database inception to June 1st, 2012.

RESULTS

Overall, out of 384 studies identified in the initial search, eight met the inclusion criteria. Studies evaluated four different types of interventions: social marketing, peer-based behavior modification, treatment, and drug law enforcement. Four studies observed a significant effect of the intervention on reducing rates of injecting initiation. Peer-based behavior modification and addiction treatment interventions were found to be most effective. Two of three studies assessing the impact of drug law enforcement on patterns of injecting initiation found no impact on injecting initiation, while one study reported inconclusive results.

CONCLUSION

There exists a limited scientific literature on strategies to prevent injecting initiation. Resources should be allocated toward increased research and development of effective interventions to prevent this phenomenon.

The effects of demand characteristics on research participant behaviours in non-laboratory settings: a systematic review

Background

The concept of demand characteristics, which involves research participants being aware of what the researcher is investigating, is well known and widely used within psychology, particularly in laboratory-based studies. Studies of this phenomenon may make a useful contribution to broader consideration of the effects of taking part in research on participant behaviour. This systematic review seeks to summarise data from studies of the effects of demand characteristics on participant behaviours in non-laboratory settings.

Methodology/Principal Findings

Electronic databases were searched to identify eligible studies. These had to be purposely designed to evaluate possible effects of demand characteristics on at least one behavioural outcome under the autonomous control of the participants and use longitudinal study designs. Only 7 studies were included, 6 providing observational data and 1 experimental study, with 5 studies involving examination of possible effects on health behaviours. Although studies provided some evidence of effects of demand characteristics on participant behaviour, heterogeneous operationalisation of the construct, the limited number of studies and poor quality of study designs made synthesis and interpretation of study findings challenging.

Conclusions/Significance

Although widely accepted as important in psychology, there have been few dedicated studies of the effects of demand characteristics on research participant behaviours outside laboratory settings. This body of literature does not currently contribute to the wider study of research participation effects. A systematic review of data from laboratory-based studies is needed, as are high-quality primary studies in non-laboratory settings. We suggest that unqualified use of the term demand characteristics should be abandoned.

Alcohol industry influence on UK alcohol policy: A new research agenda for public health

The British government has been criticised for according industry interests too much weight in alcohol policy-making. Consequently, it has been argued that alcohol strategy in the UK is built around policies for which the evidence base is weak. This has clear implications for public health. The purpose of this commentary is to map recent developments in UK alcohol policy and related debates within the alcohol policy literature, thus laying the foundations for a systematic examination of the influence of the alcohol industry on alcohol policy. It highlights the changing structure of the industry and summarises what is known about the positions and strategies of industry actors towards alcohol policy. In so doing, it aims to contribute not just to debates about alcohol policy, but to a broader understanding of health policy processes and the relationships between government and other stakeholders. It advances a new research agenda focused on the role of corporate actors in the field of alcohol policy and public health more broadly.

Effect of drug law enforcement on drug market violence: a systematic review

Violence is amongst the primary concerns of communities around the world and research has demonstrated links between violence and the illicit drug trade, particularly in urban settings. Given the growing emphasis on evidence-based policy-making, and the ongoing severe drug market violence in Mexico and other settings, we conducted a systematic review to examine the impacts of drug law enforcement on drug market violence. We conducted a systematic review using Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Specifically, we undertook a search of English language electronic databases (Academic Search Complete, PubMed, PsycINFO, EMBASE, Web of Science, Sociological Abstracts, Social Service Abstracts, PAIS International and Lexis-Nexis), the Internet (Google, Google Scholar), and article reference lists, from database inception to January 24, 2011. Overall, 15 studies were identified that evaluated the impact of drug law enforcement on drug market violence, including 11 (73%) longitudinal analyses using linear regression, 2 (13%) mathematical drug market models, and 2 (13%) qualitative studies. Fourteen (93%) studies reported an adverse impact of drug law enforcement on levels of violence. Ten of the 11 (91%) studies employing longitudinal qualitative analyses found a significant association between drug law enforcement and drug market violence. Our findings suggest that increasing drug law enforcement is unlikely to reduce drug market violence. Instead, the existing evidence base suggests that gun violence and high homicide rates may be an inevitable consequence of drug prohibition and that disrupting drug markets can paradoxically increase violence. In this context, and since drug prohibition has not meaningfully reduced drug supply, alternative regulatory models will be required if drug supply and drug market violence are to be meaningfully reduced.

Adult consequences of late adolescent alcohol consumption: a systematic review of cohort studies

BACKGROUND

Although important to public policy, there have been no rigorous evidence syntheses of the long-term consequences of late adolescent drinking.

METHODS AND FINDINGS

This systematic review summarises evidence from general population cohort studies of drinking between 15-19 years old and any subsequent outcomes aged 20 or greater, with at least 3 years of follow-up study. Fifty-four studies were included, of which 35 were assessed to be vulnerable to bias and/or confounding. The principal findings are: (1) There is consistent evidence that higher alcohol consumption in late adolescence continues into adulthood and is also associated with alcohol problems including dependence; (2) Although a number of studies suggest links to adult physical and mental health and social consequences, existing evidence is of insufficient quality to warrant causal inferences at this stage.

CONCLUSIONS

There is an urgent need for high quality long-term prospective cohort studies in order to better understand the public health burden that is consequent on late adolescent drinking, both in relation to adult drinking and more broadly. Reducing drinking during late adolescence is likely to be important for preventing long-term adverse consequences as well as protecting against more immediate harms. Please see later in the article for the Editors' Summary.

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

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.

Artikel

H. Pape: School-based interventions that seem to work: Useful research on substance use prevention or suspicious stories of success?

School-based prevention programmes targeted at adolescent substance use rarely seem to have the desired effects on behaviour. It is true that some outcome studies do conclude that such programmes have been successful, but they are relatively few and far between. Even so, one may ask whether the body of published research in this field may originate from unrealistic optimism due to publication bias and underreporting of no or counterproductive effects. Thus, anecdotal evidence suggests that the literature is biased in favour of studies with positive findings. Moreover, nearly all these studies have been carried out by programme developers, and it is well known that researchers with vested interests are more likely to bring “good news” than independent researchers. Indeed, rather than approaching the field with critical refelction, some evaluators have intended to prove that school-based prevention works and have conducted their research accordingly. Examples of questionable analytical approaches and selective reporting of positive findings are consequently not hard to find. The external validity of evaluation studies with favourable outcomes is also often questionable because they almost exclusively have assessed the effects of programmes delivered under optimal rather than real-life conditions. In conclusion, the empirical “evidence” in favour of school-based substance use prevention programmes is generally weak and does not allow recommendation of widespread dissemination of any specific programme.

Global alcohol policy and the alcohol industry

PURPOSE OF REVIEW

The WHO is preparing its global strategy on alcohol, and, in so doing, has been asked to consult with the alcohol industry on ways it could contribute in reducing the harm done by alcohol. This review asks which is more effective in reducing harm: the regulatory approaches that the industry does not favour; or the educational approaches that it does favour.

RECENT FINDINGS

The current literature overwhelmingly finds that regulatory approaches (including those that manage the price, availability, and marketing of alcohol) reduce the risk of and the experience of alcohol-related harm, whereas educational approaches (including school-based education and public education campaigns) do not, with industry-funded education actually increasing the risk of harm.

SUMMARY

The alcohol industry should not be involved in making alcohol policy. Its involvement in implementing policy should be restricted to its role as a producer, distributor, and marketer of alcohol. In particular, the alcohol industry should not be involved in educational programmes, as such involvement could actually lead to an increase in harm.