Primary prevention of cannabis use: a systematic review of randomized controlled trials

Cannabis Use During Adolescence and Young Adulthood and Academic Achievement: A Systematic Review and Meta-Analysis

Importance

Cannabis use during adolescence and young adulthood may affect academic achievement; however, the magnitude of association remains unclear.

Objective

To conduct a systematic review evaluating the association between cannabis use and academic performance.

Data Sources

CINAHL, EMBASE, MEDLINE, PsycInfo, PubMed, Scopus, and Web of Science from inception to November 10, 2023.

Study Selection

Observational studies examining the association of cannabis use with academic outcomes were selected. The literature search identified 17 622 unique citations.

Data Extraction and Synthesis

Pairs of reviewers independently assessed risk of bias and extracted data. Both random-effects models and fixed-effects models were used for meta-analyses, and the Grading of Recommendations Assessment, Development, and Evaluation approach was applied to evaluate the certainty of evidence for each outcome. Data were analyzed from April 6 to May 25, 2024.

Main Outcomes and Measures

School grades, school dropout, school absenteeism, grade retention, high school completion, university enrollment, postsecondary degree attainment, and unemployment.

Results

Sixty-three studies including 438 329 individuals proved eligible for analysis. Moderate-certainty evidence showed cannabis use during adolescence and young adulthood was probably associated with lower school grades (odds ratio [OR], 0.61 [95% CI, 0.52-0.71] for grade B and above); less likelihood of high school completion (OR, 0.50 [95% CI, 0.33-0.76]), university enrollment (OR, 0.72 [95% CI, 0.60-0.87]), and postsecondary degree attainment (OR, 0.69 [95% CI, 0.62-0.77]); and increased school dropout rate (OR, 2.19 [95% CI, 1.73-2.78]) and school absenteeism (OR, 2.31 [95% CI, 1.76-3.03]). Absolute risk effects ranged from 7% to 14%. Low-certainty evidence suggested that cannabis use may be associated with increased unemployment (OR, 1.50 [95% CI, 1.15-1.96]), with an absolute risk increase of 9%. Subgroup analyses with moderate credibility showed worse academic outcomes for frequent cannabis users and for students who began cannabis use earlier.

Conclusions and Relevance

Cannabis use during adolescence and young adulthood was probably associated with increases in school absenteeism and dropout; reduced likelihood of obtaining high academic grades, graduating high school, enrolling in university, and postsecondary degree attainment; and perhaps increased unemployment. Further research is needed to identify interventions and policies that mitigate upstream and downstream factors associated with early cannabis exposure.

[School-based cannabis prevention: Results of a cluster-randomised trial]

Acluster-randomised trial was conducted in five German federal states to evaluate the results of a school-based cannabis prevention unit. A total of 55 schools were randomly assigned to the intervention group, i.e. participation in a two-hour cannabis prevention workshop conducted by drug prevention specialists in grades 8 and 9, or to a control group with a waiting list. The knowledge, attitudes, intentions and behaviour of the young people in relation to cannabis were measured at the start of the study and six months later. 2,669 pupils(50.8% girls, average age=14.12 years) made up the sample. Effects of the intervention on the students' knowledge (adjusted regression coefficient=0.26 [0.15-0.38], p<0.001) and on the expected negative consequences of cannabis use in adolescents (adjusted regression coefficient=0.15 [0.04-0.25], p=0.006) were found. Both increased significantly more in the intervention group compared to the control group. There were no effects on other attitude-related variables, intentions or behaviour. A very short school-based workshop for grade 8 and 9 students improved their knowledge of and critical attitudes towards cannabis use, but had no effect on their future intentions and cannabis use.

Alerta Cannabis: A Tailored-Computer Web-Based Program for the Prevention of Cannabis Use in Adolescents: A Cluster-Randomized Controlled Trial Protocol

BACKGROUND

The growing use of cannabis in adolescence is a public health problem that must be addressed through prevention. In Spain, the average age of initiation of cannabis use in the adolescent population is 14.8 years. At 14 years, the lifetime prevalence of cannabis use is 11.7%, which increases to 51.,5% at the age of 18; the prevalence of cannabis use in the population aged 14 to 18 years is 28.6%, a figure that must be tried to reduce, that is why this school prevention program is proposed: Alerta Cannabis.

METHODS

The Alerta Cannabis research project consists of design, implementation, and evaluation. In the first phase, a computer-tailored eHealth program (Alerta Cannabis) is developed based on the I-Change Model, an integrated model based on three main behavioral change processes: awareness, motivation, and action. This program consists of four 30-minute sessions that will provide culturally adapted and personalized advice to motivate students not to use cannabis through text feedback, animations, and gamification techniques. This phase will also include usability testing. In the implementation phase, secondary school students from Western Andalusia, Spain (Seville, Cádiz, Huelva, and Córdoba) and Eastern Andalusia (Jaén, Málaga, and Granada) will be randomized to an experimental condition (EC) or a control condition (CC) for a cluster randomized clinical trial (CRCT). Each condition will have 35 classes within 8 schools. GI will receive the online intervention Alerta Cannabis. EC and CC will have to fill out a questionnaire at baseline, six months, and twelve months of follow-up. In the last phase, the effect of Alerta Cannabis is evaluated. The primary outcomes are the lifetime prevalence of cannabis use and its use in the last 30 days and at 6 months. At 12 months of follow-up, the prevalence in the last 12 months will also be assessed. The secondary outcome is the intention to use cannabis.

DISCUSSION

The study tests the effect of the innovative program specifically aimed to reduce the use of cannabis in the adolescent population through eHealth in Spain. The findings aim to develop and implement evidence-based cannabis prevention interventions, which could support school prevention, for instance, the assistance of school nurses. If the program proves to be effective, it could be useful to prevent cannabis use on a national and international scale.

TRIAL REGISTRATION

NCT05849636. Date of registration: March 16, 2023.

Cannabis Use and Its Impact on Mental Health in Youth in Australia and the United States: A Scoping Review

Cannabis is a widely used substance among the youth population, with an estimated 2.8% currently smoking cannabis. Its popularity is growing due to the perception of its harmless nature and lack of dependence. However, this increase in use has been linked to mental health issues, especially since its partial decriminalisation in some part of the United States and Australia. The objective of this scoping review was to investigate the mental health impact of cannabis use among young people in Australia and the United States. A scoping review was conducted according to the Joanna Briggs Institute (JBI) protocol, and articles were searched from ProQuest Central and EBSCO Host (MEDLINE and CINAHL databases). A total of 24 articles were analysed, including systematic reviews, meta-analyses, and cohort, longitudinal, and cross-sectional studies. The findings indicate that cannabis use is associated with depression, psychosis, suicide, cannabis use disorder, dependence, decline in cognitive function, and the development of externalising behaviour, particularly attention deficit hyperactivity disorder. However, the relationship between cannabis use and anxiety is equivocal. Mental health issues were more prevalent with increased frequency, duration, intensity, and type of use. Female, minority, LGBTQI, African American, Aboriginal, and Torres Strait Islander youth and the age of onset of cannabis use were significant factors for the development of mental health problems. The increasing prevalence of cannabis use among high school and college students suggests the need for intervention by teachers, parents, and community health professionals to make them aware of its potential negative mental health outcomes. Moreover, policy-level interventions by the government are required to discourage young people from using cannabis.

Influence of intrinsic and extrinsic religiosity on youth cannabis use: A structural equation modelling analysis on national survey on drug use and health (NSDUH) 2015-2019

Religiosity may reduce the risk of substance use in adults and young people. However, religiosity is a complex construct, variously defined and assessed. We explored the role of different religious components: intrinsic (subjective), extrinsic-personal (service attendance) and extrinsic-social (church-based social activities) in deterring cannabis use among adolescents. Combining several years (2015-2019) of NSDUH data on 68,263 adolescents between 12 and 17 years, a structural equation modelling (SEM) approach was used to evaluate pathways from intrinsic and extrinsic components of religiosity to cannabis use. We analyzed the role of several covariates, including comorbid depression and secular volunteering activities. About 15% of participants said they had used cannabis at some level in the previous year. Some degree of intrinsic and of extrinsic-personal religiosity was reported by 66% and 25% of the sample. 57% were committed to at least one faith-based activity, while 74% reported participation in non-faith-based community activities. The SEM regression model -controlling for putative confounders- showed that both intrinsic and extrinsic-personal religious components reduced the likelihood of cannabis use (Cannabis use coeff.: -0.065, p = 0.001; coeff.: -0.176, p < 0.001, respectively). However, the extrinsic-social component had no effect on refraining from cannabis use, despite involvement in non-faith based volunteering activities was protectively associated. Support for secular volunteering programs may be a cost-effective mechanism for reducing cannabis use. Moreover, whilst promoting religiosity is beyond the scope of any preventive programs, religious practices should be considered relevant protective factors, deserving consideration and support in terms of public health.

Towards a youth mental health paradigm: a perspective and roadmap

Most mental disorders have a typical onset between 12 and 25 years of age, highlighting the importance of this period for the pathogenesis, diagnosis, and treatment of mental ill-health. This perspective addresses interactions between risk and protective factors and brain development as key pillars accounting for the emergence of psychopathology in youth. Moreover, we propose that novel approaches towards early diagnosis and interventions are required that reflect the evolution of emerging psychopathology, the importance of novel service models, and knowledge exchange between science and practitioners. Taken together, we propose a transformative early intervention paradigm for research and clinical care that could significantly enhance mental health in young people and initiate a shift towards the prevention of severe mental disorders.

Attitudes to Cannabis Use and Public Prevention Information Among Young Adults: A Qualitative Interview Study With Implications for Prevention Practice

Background

Cannabis use carries an increased risk of ill health and social problems, especially when initiated at a young age. Drug use is influenced by individual beliefs, knowledge, and attitudes, which are, in turn, governed by social and environmental factors. In recent years, a less restrictive attitude toward cannabis has been observed in many countries, with concerns about increased cannabis use among young people. The aim of the current study was to gain a deeper understanding of young adults' attitudes toward cannabis use and public prevention information about cannabis.

Methods

A qualitative interview study was conducted among 32 anonymous informants aged 18-29 years in the Stockholm region. Participants were recruited through purposeful sampling, and semi-structured in-depth interviews were conducted using a digital video calling platform. A qualitative content analysis of the interviews was performed to generate categories and codes for cannabis use and attitudes toward prevention information.

Results

Both cannabis users and abstainers perceived some risks with cannabis; however, for many users, the positive effects appeared to outweigh any expected harm. Furthermore, the existing public information was perceived as less credible because of an excessive focus on harm. The informants expressed a desire for neutral facts about the effects of cannabis, delivered by credible senders. Moreover, they felt that prevention information should be delivered by individuals whom young people look up to or with whom they can identify, for example, people with authority or famous people such as influencers. The informants also underlined the importance of dialogue with the target group and taking young people's experiences into account when providing information about cannabis.

Conclusion

Current risk awareness associated with cannabis use among young adults is insufficient to prevent them from using cannabis. Public prevention information should preferably combine a fact-based focus on risks with recognition of cannabis' short-term desired effects, delivered by credible senders with authority or those with whom young people can identify.

Adverse and other unintended consequences of setting-based interventions to prevent illicit drug use: A systematic review of reviews

This article explores adverse and unintended consequences (AUCs) of setting-based public health interventions to prevent illicit drug use, including the mechanisms leading to these AUCs. Additionally, the reporting of AUCs in systematic reviews was assessed. Therefore, we conducted a systematic review of reviews and searched four big databases were searched. We included systematic reviews concerned with setting-based interventions to prevent illicit drug use. We used AMSTAR 2 to rate the overall confidence of the results presented in the reviews. Data on study characteristics, types and mechanisms of AUCs were extracted. An a priori categorisation of consequences drew on the WHO-INTEGRATE framework, and the categorisation of mechanisms on the Behaviour Change Wheel. For reviews reporting AUCs, the same information was also retrieved from relevant primary studies. Findings were synthesised narratively and in tables. Finally, we included 72 reviews, of which 18 reported on AUCs. From these, 11 primary studies were identified. Most of the reviews and primary studies were conducted in educational settings. The most prevalent AUCs reported in systematic reviews and primary studies were paradoxical health effects (i.e. increase of drug use). Potential mechanisms discussed primarily focussed on the change though social norms and practices. Changes of knowledge and perception were also mentioned. Concluding, the identified reviews and primary studies paid insufficient attention to AUCs of public health interventions to prevent illicit drug use. Where reported, it was mostly as an afterthought and narrowly framed as health related. No mentions of potential broader social consequences were found.

The association between age of initiation and current blunt use among adults: Findings from the national survey on drug use and health, 2014-2019

BACKGROUND

Initiating cannabis use at a young age has been linked to problematic and continued cannabis use in adulthood. Given that approximately 1 in 3 adult cannabis smokers report blunt use, it is important to determine if and how age of blunt initiation is associated with current blunt use among adult blunt smokers.

METHODS

This study uses cross-sectional pooled data from the 2014-2019 National Survey on Drug Use and Health (NSDUH) to examine the association between age of blunt initiation and current blunt use among 62,020 adults who reported lifetime blunt use.

RESULTS

Among lifetime blunt smokers, 51.4% initiated blunt use at 18 years or older, 42.1% initiated blunt use at 14-17 years old and 6.5% initiated blunt use at 13 years or younger. Multivariable logistic regression models revealed that odds of past 12-month (aOR: 1.58; 95% CI: 1.45 - 1.72), past 30-day (aOR: 2.58; 95% CI: 2.37 - 2.80) and daily (aOR: 3.17; 95% CI: 2.61 - 3.86) blunt use were greater among adults who initiated blunt use at 13 years of age or younger relative to those who initiated blunt use at 18 years of age or older, controlling for covariates.

CONCLUSIONS

Early onset of blunt use among adolescents is associated with current blunt use in adulthood among lifetime blunt users. Given the adverse health effects associated with blunt use and the prevalence of adult cannabis users who report blunt use, cannabis interventions and policies should be expanded to target blunt use among early initiators.

Lower-Risk Cannabis Use Guidelines (LRCUG) for reducing health harms from non-medical cannabis use: A comprehensive evidence and recommendations update

BACKGROUND

Cannabis use is common, especially among young people, and is associated with risks for various health harms. Some jurisdictions have recently moved to legalization/regulation pursuing public health goals. Evidence-based 'Lower Risk Cannabis Use Guidelines' (LRCUG) and recommendations were previously developed to reduce modifiable risk factors of cannabis-related adverse health outcomes; related evidence has evolved substantially since. We aimed to review new scientific evidence and to develop comprehensively up-to-date LRCUG, including their recommendations, on this evidence basis.

METHODS

Targeted searches for literature (since 2016) on main risk factors for cannabis-related adverse health outcomes modifiable by the user-individual were conducted. Topical areas were informed by previous LRCUG content and expanded upon current evidence. Searches preferentially focused on systematic reviews, supplemented by key individual studies. The review results were evidence-graded, topically organized and narratively summarized; recommendations were developed through an iterative scientific expert consensus development process.

RESULTS

A substantial body of modifiable risk factors for cannabis use-related health harms were identified with varying evidence quality. Twelve substantive recommendation clusters and three precautionary statements were developed. In general, current evidence suggests that individuals can substantially reduce their risk for adverse health outcomes if they delay the onset of cannabis use until after adolescence, avoid the use of high-potency (THC) cannabis products and high-frequency/-intensity of use, and refrain from smoking-routes for administration. While young people are particularly vulnerable to cannabis-related harms, other sub-groups (e.g., pregnant women, drivers, older adults, those with co-morbidities) are advised to exercise particular caution with use-related risks. Legal/regulated cannabis products should be used where possible.

CONCLUSIONS

Cannabis use can result in adverse health outcomes, mostly among sub-groups with higher-risk use. Reducing the risk factors identified can help to reduce health harms from use. The LRCUG offer one targeted intervention component within a comprehensive public health approach for cannabis use. They require effective audience-tailoring and dissemination, regular updating as new evidence become available, and should be evaluated for their impact.

Factors That Influence the Effectiveness of Primary Prevention of Substance Use: A Review of Reviews

Context: The fact that substance use may result in dependence and severe harm to the user and the community has led to serious and extensive endeavors to design and implement preventive interventions. Prevention programs, however, have been shown to have different effects, and that should not be taken for granted. Systematic reviews and meta-analyses in the field have tried to reveal the effects of different types of substance use prevention programs and to identify the influencing factors. Objectives: The purpose of the current review was to more accurately identify factors associated with the effectiveness of interventions or reversal of desired effects. Evidence Acquisition: We systematically reviewed systematic review and meta-analyses studies within the period of 2009 - 2019 that reported the effectiveness of substance use prevention programs. After the systematic screening of 1586 articles, 43 articles were finally reviewed. Results: In preparation for extracting our data, we designed a structural model for analyzing the results of research on the effectiveness of substance use prevention programs. In general, universal types of prevention programs were reported as more effective than the two other types of selective and indicated programs. Regarding the context of programs, the school setting was more effective than others. In the case of interventions performed in the family setting, selective programs were more effective. Interventions provided by specialists were more effective than those provided by laypeople and / or peers. Interventions provided by more than one person and from more than one discipline showed higher effectiveness. Conclusions: Based on our structural design, we feel that further studies are needed to extend our knowledge regarding the effectiveness of substance use prevention programs.

The Significance of School-based Programs, School-based Activities, and Community-Based Activities Against Marijuana Use Among Adolescents

Background: Marijuana use among adolescents is concerning in the United States, meanwhile, the effectiveness of school-based programs is inconclusive. This study examines the impact of school-based programs, school-based activities, and community-based activities on marijuana use among adolescents. Methods: A binary logistic regression analysis was conducted, using a sample of 16,509 adolescents (age = 12 to 17, male = 51.3%, White = 60.1%, Hispanic = 21.4%, African American = 14.7%, and Asian American = 3.9%) from the 2013 National Survey on Drug Use and Health (NSDUH). Results: Results of the main effects revealed that school-based programs, school-based activities, and community-based activities were deterrent factors against marijuana use among adolescents. Adolescents are less likely to use marijuana if they participate in school-based programs, school-based activities, and community-based activities. Conclusion: The findings of this study have implications for schools and those making educational policy.

Young-adult compared to adolescent onset of regular cannabis use: A 20-year prospective cohort study of later consequences

INTRODUCTION

This paper compares consequences of cannabis use initiated after high school with those of cannabis initiation in adolescence, with estimates of the proportion of adverse consequences accounted for by adult-onset and adolescent-onset cannabis users.

METHODS

A state-representative sample in Victoria, Australia (n = 1792) participated in a 10-wave longitudinal study and was followed from age 15 to 35 years. Exposure variable: Patterns of cannabis use across 20 years. Outcomes at age 35: Alcohol use, smoking, illicit drug use, relationship status, financial hardship, depression, anxiety and employment status.

RESULTS

Substantially more participants (13.6%) initiated regular use after high school (young-adult onset) than in adolescence (7.7%, adolescent onset). By the mid-30s, both young-adult and adolescent-onset regular users were more likely than minimal/non-users (63.5%) to have used other illicit drugs (odds ratio [OR] > 20.4), be a high-risk alcohol drinker (OR > 3.7), smoked daily (OR > 7.2) and less likely to be in relationships (OR < 0.4). As the prevalence of the young-adult-onset group was nearly double of the adolescent-onset group, it accounted for a higher proportion of adverse consequences than the adolescent-onset group.

DISCUSSION AND CONCLUSIONS

Cannabis users who began regular use in their teens had poorer later life outcomes than non-using peers. The larger group who began regular cannabis use after leaving high school accounted for most cannabis-related harms in adulthood. Given the legalisation of cannabis use in an increasing number of jurisdictions, we should increasingly expect harms from cannabis use to lie in those commencing use in young adulthood.

Cannabis use and cannabis use disorder

Cannabis use disorder (CUD) is an underappreciated risk of using cannabis that affects ~10% of the 193 million cannabis users worldwide. The individual and public health burdens are less than those of other forms of drug use, but CUD accounts for a substantial proportion of persons seeking treatment for drug use disorders owing to the high global prevalence of cannabis use. Cognitive behavioural therapy, motivational enhancement therapy and contingency management can substantially reduce cannabis use and cannabis-related problems, but enduring abstinence is not a common outcome. No pharmacotherapies have been approved for cannabis use or CUD, although a number of drug classes (such as cannabinoid agonists) have shown promise and require more rigorous evaluation. Treatment of cannabis use and CUD is often complicated by comorbid mental health and other substance use disorders. The legalization of non-medical cannabis use in some high-income countries may increase the prevalence of CUD by making more potent cannabis products more readily available at a lower price. States that legalize medical and non-medical cannabis use should inform users about the risks of CUD and provide information on how to obtain assistance if they develop cannabis-related mental and/or physical health problems.

Commentary on Chan & Hall (2020): Advances in specifying cannabis consumption

Cannabis consumption patterns are not evenly distributed and more frequent users, who are the minority of the population, disproportionately consume cannabis. Accurate measurement of the quantity and frequency of cannabis will require new approaches to surveillance but could lead to better assessment of the health outcomes of cannabis exposure.

Time since first cannabis use and 12-month prevalence of cannabis use disorder among youth and emerging adults in the United States

AIM

This study estimated whether and how the 12-month prevalence of cannabis use disorder among US youth aged 12-17 and emerging adults aged 18-25 varied by time since first cannabis use.

DESIGN

Repeated cross-sectional survey data from the 2015-17 National Surveys on Drug Use and Health (NSDUH).

SETTING

United States.

PARTICIPANTS

A total of 101 000 NSDUH participants aged 12-25.

MEASUREMENTS

Past 12-month cannabis use disorder was assessed using DSM-IV criteria.

FINDINGS

Among youth, the life-time prevalence of cannabis use was 15.3% [95% confidence interval (CI) = 14.86-15.65%]. Among emerging adults, the life-time prevalence of cannabis use was 52.4% (95% CI = 51.77-53.01%). The adjusted 12-month prevalence of cannabis use disorder among youth with life-time cannabis use was 10.9% (95% CI = 9.24-12.75%) in the first year after starting cannabis use, 15.3% (95% CI = 13.68-17.12%) in the second year, 17.7% (95% CI = 15.55-19.97%) in the third year and 20.6% (95% CI = 18.23-23.17%) in the fourth year and beyond, which was consistently higher after the first year (linear trend only: P < 0.0001). The adjusted 12-month prevalence of cannabis use disorder among emerging adults with life-time use ranged from 5.6% (95% CI = 4.26-7.23%) in the first year after starting cannabis use, 7.7% (95% CI = 6.45-9.17%) in the second year and 9.1% (95% CI = 7.81-10.57%) in the third year to 10.5% (95% CI = 9.87%-11.12%) in the fourth year and beyond, which was consistently higher after the first year (linear trend only: P < 0.0001). Within each time-frame since first cannabis use, the adjusted 12-month prevalence of cannabis use disorder was higher among youth life-time users than their emerging adult counterparts.

CONCLUSIONS

Among youth and emerging adults in the United States, the prevalence of cannabis use disorder appears to increase with time since initiation of use and is higher among youth than among emerging adults during each examined time-frame.

Parental Cannabis Use Is Associated with Cannabis Initiation and Use in Offspring

OBJECTIVES

To assess, before legalization in Canada, whether parental cannabis use is associated with initiation of use in adolescent offspring or with use in young-adult offspring.

STUDY DESIGN

Data were available in 2 longitudinal studies in Montréal, Canada. In AdoQuest, 1048 parents with children in grade 6 reported past-year cannabis use. Cannabis initiation among offspring was measured in grade 7, 9, and/or 11. In the Nicotine Dependence in Teens study, cannabis use data were available for 584 participants (mean age 24 years) and their parents (ie, 542 offspring-mother pairs, 438 offspring-father pairs). The association between parental and offspring cannabis use was estimated using multivariable logistic regression in both studies.

RESULTS

In AdoQuest, grade 6 never-users were 1.8 times more likely to initiate cannabis during high school if their parents reported past-year use. In the Nicotine Dependence in Teens study, the aORs (95% CI) for past-year cannabis use among adult offspring were not different for "mother uses cannabis" (2.8 [1.4-5.8]) or "father uses cannabis" (2.1 [1.2-3.8]). Participants with 1 or 2 cannabis-using parents were 1.7 and 7.1 times more likely to use cannabis, respectively, than participants with non-using parents.

CONCLUSIONS

To enable informed decision-making about their own cannabis use, parents need to be aware that children of cannabis users are more likely to use cannabis in adolescence and young adulthood.

Development and psychometric properties of the methamphetamine decisional balance scale (METH-DBS) for young adults

BACKGROUND

Drug misuse is a major problem that has an extreme negative effect on people's health. Methamphetamine (MA) is frequently used by young adults, despite its harmful consequences. The Transtheoretical Model (TTM) has been known to be very effective in explaining both the achievement and cessation of several health-related behaviors. Therefore, in this study, the TTM was used toward the domain of immoderate MA use among young adults. This study aimed to test the validity and reliability of a decisional balance scale for MA use in young adults.

METHODS

A multi-phase scale development approach was used to develop the scale. First, 41 university students enrolled in a qualitative study that generated content for a primary set of a 40-item instrument. In order to produce a pre-final version of the instrument, face and content validity were calculated in the next step. The instrument validation was assessed with a sample of 250 university students. Then, the construct validity (exploratory and confirmatory), convergent validity, discriminate validity, internal consistency applying test-retest reliability, and Cronbach's alpha of the scale were measured.

RESULTS

Forty items were initially generated from the qualitative data. After content validity, this amount was reduced to 25 items. The exploratory factor analysis revealed four factors (self and other cons, coping and social pros) containing 21 items that jointly accounted for 55.24% of the observed variance. The confirmatory factor analysis indicated a model with appropriate fitness for the data. Cronbach's alpha coefficient for the dimensions ranged from .74 to .87, and the Intraclass Correlation Coefficient (ICC) ranged from .83 to .91, which is within acceptable ranges.

CONCLUSION

The findings showed that the Methamphetamine Decisional Balance Scale is a valid and reliable scale that increases our ability to study motivational factors related to MA use among young adult. Consequently, the instrument could be applied in both practice and future studies.

Universal cannabis outcomes from the Climate and Preventure (CAP) study: a cluster randomised controlled trial

Background

The Climate and Preventure (CAP) study was the first trial to assess and demonstrate the effectiveness of a combined universal and selective approach for preventing alcohol use and related harms among adolescents. The current paper reports universal effects from the CAP study on cannabis-related outcomes over three years.

Methods

A cluster randomized controlled trial was conducted with 2190 students from twenty-six Australian high schools (mean age: 13.3 yrs., SD 0.48). Participants were randomised to one of four conditions; universal prevention for all students (Climate); selective prevention for high-risk students (Preventure); combined universal and selective prevention (Climate and Preventure; CAP); or health education as usual (Control). Participants were assessed at baseline, post intervention (6–9 months post baseline), and at 12-, 24- and 36-months, on measures of cannabis use, knowledge and related harms. This paper compares cannabis-related knowledge, harms and cannabis use in the Control, Climate and CAP groups as specified in the protocol, using multilevel mixed linear models to assess outcomes.

Results

Compared to Control, the Climate and CAP groups showed significantly greater increases in cannabis-related knowledge initially (p <  0.001), and had higher knowledge at the 6, 12 and 24-month follow-ups. There was no significant difference between the Climate and CAP groups. While no differences were detected between Control and the CAP and Climate groups on cannabis use or cannabis-related harms, the prevalence of these outcomes was lower than anticipated, possibly limiting power to detect intervention effects. Additional Bayesian analyses exploring confidence in accepting the null hypothesis showed there was insufficient evidence to conclude that the interventions had no effect, or to conclude that they had a meaningfully large effect.

Conclusions

Both the universal Climate and the combined CAP programs were effective in increasing cannabis-related knowledge for up to 2 years. The evidence was inconclusive regarding whether the interventions reduced cannabis use and cannabis-related harms. A longer-term follow-up will ascertain whether the interventions become effective in reducing these outcomes as adolescents transition into early adulthood.

Trial registration

This trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12612000026820) on the 6th of January 2012, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=347906&isReview=true

Electronic supplementary material

The online version of this article (10.1186/s13011-018-0171-4) contains supplementary material, which is available to authorized users.

Effectiveness of Fresh Start: A Randomized Study of a School-Based Program to Retain a Negative Attitude Toward Substance Use in Secondary School Freshmen

BACKGROUND

The transition to secondary school is linked to more positive attitudes toward substance use, which prelude the moment of first use. Fresh Start is a school-based prevention program for secondary school freshmen (12-13 years old) to retain negative attitudes.

OBJECTIVES

This study evaluates the effectiveness of Fresh Start on the attitudes toward smoking, alcohol use, and cannabis use, and on multiple secondary outcome measures. In addition, the effect of timing of the program within the schoolyear was examined.

METHODS

A cluster randomized trial was conducted. 48 classes, containing 1083 secondary school freshmen, were randomly allocated to the experimental or waiting list control condition. Experimental classes completed Fresh Start between October 2015 and January 2016 and waiting list control classes completed Fresh Start between March 2016 and May 2016. Measurements were scheduled at three points in time (September 2015, February 2016, and June 2016). Data were analyzed by means of multilevel analyses.

RESULTS

Fresh Start had small but significant effects on the attitudes toward smoking, alcohol use and cannabis use. The majority of secondary outcome measures were not influenced by Fresh Start, although a small, adverse effect was found on the perceived social acceptance of cannabis use by friends. Timing of the intervention within the schoolyear did not influence its effectiveness. Conclusions/Importance: Fresh Start can help to delay the development of positive attitudes toward substance use in secondary school freshmen. Strengths and limitations, implications for practice and suggestions for future research are discussed.

Risk factors and peripheral biomarkers for schizophrenia spectrum disorders: an umbrella review of meta-analyses

OBJECTIVE

This study aimed to systematically appraise the meta-analyses of observational studies on risk factors and peripheral biomarkers for schizophrenia spectrum disorders.

METHODS

We conducted an umbrella review to capture all meta-analyses and Mendelian randomization studies that examined associations between non-genetic risk factors and schizophrenia spectrum disorders. For each eligible meta-analysis, we estimated the summary effect size estimate, its 95% confidence and prediction intervals and the I2 metric. Additionally, evidence for small-study effects and excess significance bias was assessed.

RESULTS

Overall, we found 41 eligible papers including 98 associations. Sixty-two associations had a nominally significant (P-value <0.05) effect. Seventy-two of the associations exhibited large or very large between-study heterogeneity, while 13 associations had evidence for small-study effects. Excess significance bias was found in 18 associations. Only five factors (childhood adversities, cannabis use, history of obstetric complications, stressful events during adulthood, and serum folate level) showed robust evidence.

CONCLUSION

Despite identifying 98 associations, there is only robust evidence to suggest that cannabis use, exposure to stressful events during childhood and adulthood, history of obstetric complications, and low serum folate level confer a higher risk for developing schizophrenia spectrum disorders. The evidence on peripheral biomarkers for schizophrenia spectrum disorders remains limited.

A Meta-analysis of the Effectiveness of Interactive Middle School Cannabis Prevention Programs

This meta-analysis examines the effectiveness of interactive middle school-based drug prevention programs on adolescent cannabis use in North America, as well as program characteristics that could moderate these effects. Interactive programs, compared to more didactic, lecture style programs, involve participants in skill-building activities and focus on interaction among participants. A systematic literature search was conducted for English-language studies from January 1998 to March 2014. Studies included evaluations using random assignment or a quasi-experimental design of interactive school-based substance use prevention programs delivered to adolescents (aged 12-14) in North American middle schools (grades 6-8). Data were extracted using a coding protocol. The outcomes of interest were post-treatment cannabis use, intent to use, and refusal skills compared across intervention and control groups. Effect sizes (Cohen's d) were calculated from continuous measures, and dichotomous measures were converted to the d index. A total of 30 studies yielding 23 independent samples were included. The random effects pooled effect size for cannabis use (k = 21) was small ([Formula: see text]= -0.07, p < 0.01) and favorable for the prevention programs. The pooled effect sizes for intention to use (k = 3) and refusal skills (k = 3) were not significant. Moderator analyses indicated significant differences in program effectiveness between instructor types, with teachers found to be most effective ([Formula: see text]= -0.08, p = 0.02). The findings provide further support for the use of interactive school-based programs to prevent cannabis use among middle school students in North America.

Time Trends of Cannabis Use Among Treatment-seeking Individuals at Government De-addiction Centers Across India Over a Period of 7 Years

BACKGROUND

Cannabis continues to be the most commonly used illicit psychoactive substance globally. The National Survey in India conducted in the year 2004 also reported it to be the most commonly used illicit substance in the country. Furthermore, it was reported to be the second most commonly used psychoactive substance by the treatment seekers at de-addiction centers in the country.

OBJECTIVES

To assess time trends of cannabis use among treatment-seeking individuals at government de-addiction centers across India over a period of 7 years.

MATERIALS AND METHODS

The study utilized data collected through Drug Abuse Monitoring System across India. The data of treatment seekers from de-addiction centers established under the Drug De-addiction Program, Ministry of Health and Family Welfare, Government of India and supported by the Ministry of Social Justice and Empowerment, Government of India (122 in number) across the country were analyzed.

RESULTS

A total of 107,469 individuals sought treatment from government de-addiction centers over the 7 years (2007-2013) period. With the exception of an aberration for the year 2012, there has been a steady decline in the proportion of treatment seekers who are not current cannabis users. A significantly greater proportion (Chi-square: 586.30, df: 1, P < 0.001) of individuals with current cannabis use alone or along with tobacco (20.4%) tend to have a co-morbid psychiatric disorder as compared to treatment seekers with current use of substances other than cannabis (6.1%).

CONCLUSIONS

It is important to focus on cannabis in clinical service delivery and research in the country.

Co-Occurrence of Substance-Related and Other Mental Health Disorders Among Adolescent Cannabis Users

OBJECTIVE

Cannabis is the most commonly used illicit substance in the United States and is increasingly being legalized throughout the United States. Many believe that cannabis is relatively harmless, and some believe that cannabis is not addictive. We wondered what the rates of cannabis abuse and dependence might be among adolescents referred for substance use evaluations and also about the incidence of co-occurring psychiatric illnesses and substance use disorders among those individuals.

METHODS

Herein, we analyze intake data from 483 adolescents referred for evaluation at an adolescent substance abuse clinic, with information gleaned from the adolescents and their parents or caregivers.

RESULTS

Forty-seven percent of our sample met the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) criteria for cannabis dependence and another 32% for cannabis abuse. Among adolescents with cannabis use disorders, the co-occurrence of alcohol and opioid abuse or dependence was high. These individuals also suffered from significant psychiatric comorbidities otherwise.

CONCLUSIONS

Our results show that cannabis use carries the risk of dependence and also carries with it significant risk of comorbidities, both with respect to other substance use disorders and other psychiatric illness. Given the growing body of research linking cannabis use with addiction and other psychiatric illness, public health efforts ought to center on the potential dangers of cannabis use.

Early interventions in risk groups for schizophrenia: what are we waiting for?

Intervention strategies in adolescents at ultra high-risk (UHR) for psychosis are promising for reducing conversion to overt illness, but have only limited impact on functional outcome. Recent studies suggest that cognition does not further decline during the UHR stage. As social and cognitive impairments typically develop before the first psychotic episode and even years before the UHR stage, prevention should also start much earlier in the groups at risk for schizophrenia and other psychiatric disorders. Early intervention strategies could aim to improve stress resilience, optimize brain maturation, and prevent or alleviate adverse environmental circumstances. These strategies should urgently be tested for efficacy: the prevalence of ~1% implies that yearly ~22 in every 100,000 people develop overt symptoms of this illness, despite the fact that for many of them—e.g., children with an affected first-degree family member or carriers of specific genetic variants—increased risk was already identifiable early in life. Our current ability to recognize several risk groups at an early age not only provides an opportunity, but also implies a clinical imperative to act. Time is pressing to investigate preventive interventions in high-risk children to mitigate or prevent the development of schizophrenia and related psychiatric disorders.

Prevention, early intervention, harm reduction, and treatment of substance use in young people

We did a systematic review of reviews with evidence on the effectiveness of prevention, early intervention, harm reduction, and treatment of problem use in young people for tobacco, alcohol, and illicit drugs (eg, cannabis, opioids, amphetamines, or cocaine). Taxation, public consumption bans, advertising restrictions, and minimum legal age are effective measures to reduce alcohol and tobacco use, but are not available to target illicit drugs. Interpretation of the available evidence for school-based prevention is affected by methodological issues; interventions that incorporate skills training are more likely to be effective than information provision-which is ineffective. Social norms and brief interventions to reduce substance use in young people do not have strong evidence of effectiveness. Roadside drug testing and interventions to reduce injection-related harms have a moderate-to-large effect, but additional research with young people is needed. Scarce availability of research on interventions for problematic substance use in young people indicates the need to test interventions that are effective with adults in young people. Existing evidence is from high-income countries, with uncertain applicability in other countries and cultures and in subpopulations differing in sex, age, and risk status. Concerted efforts are needed to increase the evidence base on interventions that aim to reduce the high burden of substance use in young people.

Limitations to the Dutch cannabis toleration policy: Assumptions underlying the reclassification of cannabis above 15% THC

The Netherlands has seen an increase in Δ9-tetrahydrocannabinol (THC) concentrations from approximately 8% in the 1990s up to 20% in 2004. Increased cannabis potency may lead to higher THC-exposure and cannabis related harm. The Dutch government officially condones the sale of cannabis from so called 'coffee shops', and the Opium Act distinguishes cannabis as a Schedule II drug with 'acceptable risk' from other drugs with 'unacceptable risk' (Schedule I). Even in 1976, however, cannabis potency was taken into account by distinguishing hemp oil as a Schedule I drug. In 2011, an advisory committee recommended tightening up legislation, leading to a 2013 bill proposing the reclassification of high potency cannabis products with a THC content of 15% or more as a Schedule I drug. The purpose of this measure was twofold: to reduce public health risks and to reduce illegal cultivation and export of cannabis by increasing punishment. This paper focuses on the public health aspects and describes the (explicit and implicit) assumptions underlying this '15% THC measure', as well as to what extent these are supported by scientific research. Based on scientific literature and other sources of information, we conclude that the 15% measure can provide in theory a slight health benefit for specific groups of cannabis users (i.e., frequent users preferring strong cannabis, purchasing from coffee shops, using 'steady quantities' and not changing their smoking behaviour), but certainly not for all cannabis users. These gains should be weighed against the investment in enforcement and the risk of unintended (adverse) effects. Given the many assumptions and uncertainty about the nature and extent of the expected buying and smoking behaviour changes, the measure is a political choice and based on thin evidence.

Technology-based interventions for tobacco and other drug use in university and college students: a systematic review and meta-analysis

Background

University students have high levels of tobacco and other drug use, yet they are unlikely to seek traditional care. Technology-based interventions are highly relevant to this population. This paper comprises a systematic review and meta-analysis of published randomized trials of technology-based interventions evaluated in a tertiary (university/college) setting for tobacco and other drug use (excluding alcohol). It extends previous reviews by using a broad definition of technology.

Methods

PubMed, PsycInfo, and the Cochrane databases were searched using keywords, phrases, and MeSH terms. Retrieved abstracts (n = 627) were double screened and coded. Included studies met the following criteria: (1) the study was a randomized trial or a randomized controlled trial (RCT); (2) the sample was composed of students attending a tertiary (e.g., university, college) institution; (3) the intervention was either delivered by or accessed using a technological device or process (e.g., computer/internet, telephone, mobile short message services [SMS]); (4) the age range or mean of the sample was between 18 and 25 years; and (5) the intervention was designed to alter a drug use outcome relating to tobacco or other drugs (excluding alcohol).

Results

A total of 12 papers met inclusion criteria for the current review. The majority of included papers examined tobacco use (n = 9; 75%), two studies targeted marijuana use (17%); and one targeted stress, marijuana, alcohol, and tobacco use. A quantitative meta-analysis was conducted on the tobacco use studies using an abstinence outcome measure (n = 6), demonstrating that the interventions increased the rate of abstinence by 1.5 times that of controls (Risk Ratio [RR] = 1.54; 95% Confidence Interval [CI] = 1.20–1.98). Across all 12 studies, a total of 20 technology-based interventions were reviewed. A range of technology was employed in the interventions, including stand-alone computer programs (n = 10), internet (n = 5), telephone (n = 3), and mobile SMS (n = 2).

Conclusions

Although technological interventions have the potential to reduce drug use in tertiary students, very few trials have been conducted, particularly for substances other than tobacco. However, the improvement shown in abstinence from tobacco use has the potential to impact substantially on morbidity and mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s13722-015-0027-4) contains supplementary material, which is available to authorized users.

Development of a brief substance use sensation seeking scale: validation and prediction of injection-related behaviors

Sensation seeking, a personality trait, has been shown to predict engagement in high-risk behaviors. However, little is known regarding the impact of sensation seeking on substance use among street youth. We therefore sought to modify a sensation seeking scale (SSS) for use among this population. Street youth from the Vancouver-based At-Risk Youth Study (n = 226) completed the modified SSS. Exploratory and confirmatory factor analysis (EFA/CFA) were undertaken to establish the scale's dimensionality and internal validity. The association between SSS score and injection-related behaviors was tested using generalized estimating equation analysis. EFA results indicated scale unidimensionality. The comparative fit index (CFI) suggested acceptable fit (CFI = 0.914). In multivariate analysis, sensation seeking was independently associated with injection drug use, crystal methamphetamine use, polysubstance use, and binge drug use (all p < 0.05). Our findings provide preliminary support for the use of the modified SSS among street youth.

Perceived role legitimacy and role importance of Australian school staff in addressing student cannabis use

The high prevalence of cannabis use by Australian secondary school students makes schools an ideal setting for the delivery of substance use prevention programs. Although efficacious school-based cannabis prevention programs exist, there is scant research investigating the perceived role legitimacy and role importance of school staff. As such, this study surveyed a sample of 1691 Australian school staff by utilizing Generation Next seminars which are attended by professionals working with young people. The self-completed survey identified that, despite elevated contact with students relative to other school staff, teachers reported the least role importance and legitimacy of all school staff. Further, teachers reported the lowest level of staff drug education training, which was an important predictor of an increased feeling of role importance and legitimacy among school staff.

Experiences of Australian school staff in addressing student cannabis use

Cannabis is the most frequently used illicit drug by Australian secondary school students yet there is scant research investigating school staff responses to student cannabis use. As such, this study surveyed 1,692 school staff who attended Generation Next seminars throughout Australia. The self-complete survey identified that the majority of school staff had discussed cannabis use at least once in the past year, although teachers were less likely to report having cannabis-related discussions compared to other school staff. Staff drug education training was consistently associated with an increased prevalence of cannabis-related discussion and assistance. These findings highlight a need for drug education among school staff and particularly among teachers.