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Intervenciones escolares breves y resultados conductuales para los adolescentes que consumen drogas

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References

References to studies included in this review

McCambridge 2004 {published data only}

*McCambridge J, Strang J. The efficacy of single‐session motivational interviewing in reducing drug consumption and perceptions of drug‐related risk and harm among young people: results from a multisite cluster randomized trial. Addiction 2004;99:39‐52.
McCambridge J, Strang J. Deterioration over time in effect of motivational interviewing in reducing drug consumption and related risk among young people. Journal of Substance Abuse Treatment 2005;100:470‐8.

McCambridge 2008 {published data only}

McCambridge J, Slym, RL, Strang, J. Randomized controlled trial of motivational interviewing compared with drug information and advice for early intervention among young cannabis users. Addiction 2008;103:1809‐18.

Walker 2011 {published data only}

Walker DD, Stephens R, Roffman R, DeMarce J, Lozano B, Towe S, et al. Randomized controlled trial of motivational enhancement therapy with nontreatment‐seeking adolescent cannabis users: a further test of the teen marijuana check‐up. Psychology of Addictive Behaviors 2011;25(3):474‐84.

Werch 2005 {published data only}

Werch C, Jobli E, Moore, MJ, DiClemente CC, Dore, H, Brown CH. A brief experimental alcohol beverage‐tailored program for adolescents. Journal of Studies on Alcohol 2005;65:284‐90.

Winters 2007b {published data only}

Winters KC, Leitten W. Brief intervention for drug‐abusing adolescents in a school setting. Psychology of Addictive Behaviors 2007;21(2):249–54.

Winters 2012 {published data only}

Winters KC, Fahnhorst T, Botzet A, Lee S, Lalone B. Brief intervention for drug‐abusing adolescents in a school setting: Outcomes and mediating factors. Journal of Substance Abuse Treatment 2012;42:279–88.
Winters KC, Lee S, Botzet A, Fahnhorst T, Nicholson A. One‐year outcomes and mediators of a brief intervention for drug abusing adolescents. Psychology of Addictive Behaviors 2014;28(2):464‐74.

References to studies excluded from this review

Apsler 2006 {published data only}

Apsler R, Formica S, Fraster B, McMahan R. Promoting positive adolescent development for at‐risk students with a student assistance program. The Journal of Primary Prevention 2006;27(6):533‐54.

Armitage 2014 {published data only}

Armitage CJ, Rowe R, Arden MA, Harris PR. A brief psychological intervention that reduces adolescent alcohol consumption. Journal of Consulting and Clinical Psychology 2014;82(3):546‐50.

Baer 1992 {published data only}

Baer S, Marlatt GA, Kivlahan DR, Fromme K, Larimer ME, Williams E. An experimental test of three methods of alcohol risk reduction with young adults. Journal of Consulting and Clinical Psychology 1992;60(6):974‐9.

Barnett 2012 {published data only}

Barnett E, Spruijt‐Metz D, Unger JB, Sun P, Rohrbach LA, Sussman S. Boosting a teen substance use prevention program with motivational interviewing. Substance Use and Misuse 2012;47(4):418‐28.

Bear 2008 {published data only}

Bear JS, Beadnell B, Garrett SB, Hartzler B, Wells EA, Peterson PL. Adolescent change language within a brief motivational intervention and substance use outcomes. Psychology of Addictive Behaviors 2008;22(4):570–5.

Cirillo 1998 {published data only}

Cirillo KJ, Pruitt BE, Colwell B, Kingery PM, Hurley RS, Ballard D. School violence: Prevalence and intervention strategies for at‐risk adolescents. Adolescence 1998;33(130):319‐30.

Conrod 2013 {published data only}

Conrod PJ, O'Leary‐Barrett M, Newton N, Topper L, Castellanos‐Ryan, MacKie C, et al. Effectiveness of a selective, personality‐targeted prevention program for adolescent alcohol use and misuse: a cluster randomized controlled trial. JAMA Psychiatry 2013;70(3):334‐42.

D'Amico 2002 {published data only}

D'Amico EJ, Fromme K. Brief prevention for adolescent risk‐taking behavior. Addiction 2002;97:563‐74.

D'Amico 2013 {published data only}

D'Amico EJ, Hunter SB, Miles JNV, Ewing BA, Osilla KC. A randomized controlled trial of a group motivational interviewing intervention for adolescents with a first time alcohol or drug offense. Journal of Substance Abuse Treatment 2013;45(5):400‐8.

de Gee 2014 {published data only}

de Gee EA, Verdurmen JEE, Bransen E, de Jonge JM, Schippers GM. A randomized controlled trial of a brief motivational enhancement for non‐treatment‐seeking adolescent cannabis users. Journal of Substance Abuse Treatment 2014;47(3):181‐8.

Dennis 2004 {published data only}

Dennis M, Godley SH, Diamond G, Tims FM, Babor T, Donaldson J, et al. The cannabis youth treatment (CYT) experiment: main findings from two randomized trials. Journal of Substance Abuse Treatment 2004;27:197–213.

Doumas 2014 {published data only}

Doumas DM, Hausheer R, Esp S, Cuffee C. Reducing alcohol use among 9th grade students: 6 month outcomes of a brief, Web‐based intervention. Journal of Substance Abuse Treatment 2014;47(1):102‐5.

Gray 2005 {published data only}

Gray E, McCambridge J, Strang J. The effectiveness of motivational interviewing delivered by youth workers in reducing drinking, cigarette and cannabis smoking among young people: a quasi‐experimental study. Alcohol and Alcoholism 2005;40(6):535–9.

Hecht 2003 {published data only}

Hecht ML, Marsiglia FF, Elek E, Wagstaff, DA, Kulis S, Dustman P, et al. Culturally grounded substance use prevention: An evaluation of the keepin’ it R.E.A.L. curriculum. Prevention Science 2003;4(4):233‐48.

Marsden 2006 {published data only}

Marsden J, Stillwell G, Barlow H, Boys A, Taylor C, Hunt N, et al. An evaluation of a brief motivational intervention among young ecstasy and cocaine users: no effect on substance and alcohol use outcomes. Addiction 2006;101:1014‐26.

Martin 2008 {published data only}

Martin G, Copeland J. The adolescent cannabis check‐up: Randomized trial of a brief intervention for young cannabis users. Journal of Substance Abuse Treatment 2008;34:407‐14.

Newbury‐Birch 2014 {published data only}

Newbury‐Birch D, O'Neil S, O'Donnell A, Coulton S, Howel D, McColl E, et al. A pilot feasiblity C‐RCT of screening and brief alcohol intervention in young people aged 14‐15 in a high school setting: Sips Jr‐high. Alcoholism: Clinical and Experimental Research 2014;38(S1):127A.

Peleg 2001 {published data only}

Peleg A, Neumann L, Friger M, Peleg R, Sperber AD. Outcomes of a brief alcohol abuse prevention program for Israeli high school students. Journal of Adolescent Health 2001;28:263–9.

Saunders 2004 {published data only}

Saunders JB, Kypri K, Walters ST, Laforge RG, Larimer ME. Approaches to brief intervention for hazardous drinking in young people. Alcoholism: Clinical and Experimental Research 2004;28(2):322‐9.

Sinha 2003 {published data only}

Sinha R, Easton C, Renee‐Aubin L, Carroll KM. Engaging young probation‐referred marijuana‐abusing individuals in treatment: a pilot trial. The American Journal on Addictions 2003;12:314‐23.

Spoth 2001 {published data only}

Spoth RL, Redmond C, Shin C. Randomized trial of brief family interventions for general populations: adolescent substance use outcomes 4 years following baseline. Journal of Consulting and Clinical Psychology 2001;69(4):627‐42.

Srisurapanont 2007 {published data only}

Srisurapanont M, Sombatmai S, Boripuntakul T. Brief intervention for students with methamphetamine use disorders: a randomized controlled trial. The American Journal on Addictions 2007;16:111‐6.

Thaker 2008 {published data only}

Thaker S, Steckler V, Khataopush S, Rose J, Hallforts D. Program characteristics and organizational factors affecting the implementation of a school‐based indicated prevention program. Health Education Research 2007;23(2):238‐48.

Tubman 2002 {published data only}

Tubman JG, Wagner EF, Gil AG, Pate KN. Brief motivational intervention for substance‐abusing delinquent adolescents: guided self‐change as a social work practice innovation. Health and Social Work 2002;27(3):208‐12.

Wagner 2014 {published data only}

Wagner EF, Hospital MM, Graziano JN, Morris SL, Gil AG. A randomized controlled trial of guided self‐change with minority adolescents. Journal of Consulting and Clinical Psychology 2014;82(6):1128‐39.

Werch 1999 {published data only}

Werch CE, Pappas DM, Carlson JM, DiClemente CC. Six‐month outcomes of an alcohol prevention program for inner‐city youth. American Journal of Health Promotion 1999;13(4):237‐40.

Werch 2010 {published data only}

Werch CE, Bian H, Diclemente CC, Moore MJ, Thombs D, Ames SC, et al. A brief image‐based prevention intervention for adolescents. Psychology of Addictive Behaviours 2010;24(1):170‐5.

Williams 2007 {published data only}

Williams AV, Meyer E, Pechansky F. Development of a therapeutic game for relapse prevention and motivation for change in young drug users [Desenvolvimento de um jogo terapêutico para prevenção da recaída e motivação para mudança em Jovens usuários de drogas]. Psicologia: Teoria e Pesquisa 2007;23(4):407‐14.

Wu 2003 {published data only}

Wu Y, Stanton BF, Galbraith J, Kaljee L, Cottrell L, Li X, et al. Sustaining and broadening intervention impact: a longitudinal randomized trial of 3 adolescent risk reduction approaches. Pediatrics 2003;111(1):e32‐8.

Babor 2007

Babor TF, McRee BG, Kassebaum PA, Grimaldi PL, Ahmed K, Bray J. Screening, Brief Intervention, and Referral to Treatment (SBIRT). Substance Abuse 2007;28(3):7‐30.

Barry 1999

Barry KL. Brief Interventions and Brief Therapies for Substance Abuse. Treatment Improvement Protocol (TIP) Series 34. Center for Substance Abuse Treatment, 1999.

Bien 1993

Bien TH, Miller WR, Tonigan SJ. Brief interventions for alcohol problems: a review. Addiction 1993;88:315‐36.

Bingham 2010

Bingham CR, Barretto AI, Walton MA, Bryant CM, Shope JT, Raghunathan TE. Efficacy of a web‐based, tailored, alcohol prevention/intervention program for college students: initial findings. Journal of American College Health 2010;58(4):349‐56.

Boutron 2007

Boutron I, Guittet L, Estellat C, Moher D, Hrobjartsson A, Ravaud P. Reporting methods of blinding in randomized trials assessing nonpharmacological treatments. PL oS Medicine 2007;4(2):370‐80.

Brunelle 2000

Brunelle N, Brochu S, Cousineau MM. Drug‐crime relations among drug‐consuming juvenile delinquents: a tripartite model and more. Contemporary Drug Problems 2000;27:835‐66.

Campbell 2000

Campbell MK, Mollison J, Steen N, Grimshaw JM, Eccles M. Analysis of cluster randomised trials in primary care: a practical approach. Family Practice 2000;17(2):192‐6.

CONSORT 2010

CONSORT 2010. Consolidated Standards of Reporting Trials. Library for health research reporting. http://www.equator‐network.org/resource‐centre/library‐of‐health‐research‐reporting/ (accessed 16 July 2010).

Corneau 2004

Corneau M, Lanctôt N. Mental health outcomes of adjudicated males and females: the aftermath of juvenile delinquency. Criminal Behavior and Mental Health 2004;14:251‐62.

Feldstein 2006

Feldstein SW, Miller WR. Substance use and risk‐taking among adolescents. Journal of Mental Health 2006;15(3):633‐43.

Gore 2011

Gore FM, Bloem PJN, Patton GC, Ferguson J, Joseph V, Coffey C, et al. Global burden of disease in young people aged 10–24 years: a systematic analysis. The Lancet 2011;377:2093–102.

GRADE 2004

The GRADE working group. Grading quality of evidence and strength of recommendations. BMJ 2004;328:1490‐4.

Guyatt 2008

Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck‐Ytter Y, Alonso‐Coello P, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 2008;336(7650):924‐6.

Guyatt 2011

Guyatt G, Oxman AD, Akl EA, Kunz R, Vist G, Brozek J, et al. GRADE guidelines 1. Introduction‐GRADE evidence profiles and summary of findings tables. Journal of Clinical Epidemiology 2011;64:383‐94.

Hallfors 2006

Hallfors D, Cho H, Brodish PH, Flewelling R, Khatapoush S. Identifying high school students "at risk" for substance use and other problems: implication for prevention. Substance Use and Misuse 2006;41:1‐15.

Hibell 2012

Hibell B, Guttormsson U. The 2011 ESPAD Report: Substance Use Among Students in 36 European Countries. ESPAD Report2012.

Higgins 2011

Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011].. The Cochrane Collaboration. www.cochrane‐handbook.org 2011.

Hingson 2006

Hingson RW, Heeren T, Winter MR. Age of alcohol‐dependence onset: associations with severity of dependence and seeking treatment. Pediatrics 2006;11(3):e755‐63. [DOI: 10.1542/peds.2006‐0223]

International Center for Alcohol Policies 2010

International Center for Alcohol Policies. Washington, DC: International Center for Alcohol Policies; 2010. ICAP Blue Book Module 12: Legal Age Limits. Practical Guides for Alcohol Policy and Prevention Approaches.

Jackson 2013

Jackson K, Schulenberg J. Alcohol use during the transition from middle school to high school: national panel data on prevalence and moderators. Developmental Psychology 2013;49(11):2147‐58. [DOI: 10.1037/a0031843]

Jensen 2011

Jensen CD, Cushing CC, Aylward BS, Craig JT, Sorell DM, Steele RG. Effectiveness of motivational interviewing interventions for adolescent substance use behavior change: a meta‐analytic review. Journal of Consulting and Clinical Psychology 2011;79(4):433‐40.

Johnston 2015

Johnston LD, O’Malley PM, Miech RA, Bachman JG, Schulenberg JE. Monitoring the Future National Survey Results on Drug Use: 1975‐2014: Overview, Key Findings on Adolescent Drug Use. Ann Arbor: Institute for Social Research, The University of Michigan, 2015.

Kann 2013

Kann L, Kinchen S, Shanklin SL, Flint KH, Hawkins J, Harris WA, et al. Youth risk behavior surveillance — United States, 2013. Morbidity and Mortality Weekly Report. Surveillence Summaries 2014;63(Supplement 4):1‐168.

Kutcher 2009

Kutcher S, McDougall A. Problems with access to adolescent mental health care can lead to dealings with the criminal justice system. Paediatrics & Child Health 2009;14(1):15‐8.

Lanctôt 2007

Lanctôt N, Cernkovich SA, Giordano PC. Delinquent behaviour, official delinquency and gender consequences for adulthood functioning and well‐being. Criminology 2007;45(1):131‐57.

Leoschut 2007

Leoschut L, Bonora A. Offender Perspective on Violent Crime. Someone Stole My Smile: An Exploration Into the Causes of Youth Violence in South Africa2007; Vol. Monograph Series, No. 3.

Miller 2002

Miller WR, Rollnick S. Motivational Interviewing: Preparing People to Change Addictive Behavior. 2nd Edition. New York: Guilford Press, 2002.

Moyer 2002

Moyer A, Finney JW, Swearingen CE, Vergun P. Brief interventions for alcohol problems: a meta‐analytic review of controlled investigations in treatment‐seeking and non‐treatment seeking populations. Addiction 2002;97:279‐92.

Mulvey 2010

Mulvey EP, Schubert CA, Chassin LA. Substance Use and Delinquent Behavior Among Serious Adolescent Offenders. Juvenile Justice2010:Washington, DC: Office of Juvenile Justice and Delinquency Prevention.

NICE 2007

National Institute for Health and Clinical Excellence. School‐based interventions on alcohol. NICE Public Health Guidance Report2007; Vol. 7:1‐46.

Patton 2014

Patton R, Deluca P, Kaner E, Newbury‐Birch D, Phillips T, Drummond C. Alcohol screening and brief intervention for adolescents: The how, what and where of reducing alcohol consumption and related harm among young people. Alcohol & Alcoholism 2014;49(2):207‐12. [DOI: 10.1093/alcalc/agt165]

Plüddemann 2010

Plüddemann A, Flisher AJ, Mathews C, Parry CDH, Lombard CA. Methamphetamine use, aggressive behaviour and other mental health issues among high‐school students in Cape Town, South Africa. Drug and Alcohol Dependence 2010;109:14‐9.

Prochaska 1993

Prochaska JO, DeClemente CC, Norcross JC. In search of how people change: applications to addictive behaviors. Journal of Addictions Nursing 1993;15(1):2‐16.

Reddy 2013

Reddy SP, James S, Sewpaul R, Sifunda S, Ellahebokus A, Kambaran NS, et al. Umthente Uhlaba Usamila – The 3rd South African National Youth Risk Behaviour Survey 2011. Cape Town: South African Medical Research Council, 2013.

RevMan 2014

Review Manager (RevMan) [Computer program]. Version 5.3. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014.

Rollnick 1995

Rollnick S, Miller WR. What is motivational interviewing?. Behavioural and Cognitive Psychotherapy 1995;23:325‐34.

Schünemann 2006

Schünemann HJ, Jaeschke R, Cook D, Bria W, El‐Solh A, Ernst A, et al. An official ATS statement: grading the quality of evidence and strength of recommendations in ATS guidelines and recommendations. American Journal of Respiratory and Critical Care Medicine 2006;174:605‐14.

Storr 2007

Storr CL, Accornero VH, Crum RM. Profiles of disruptive behaviour: association with recent drug consumption among adolescents. Addictive Behaviors 2007;32:248‐64.

Tait 2003

Tait RJ, Hulse GK. A systematic review of the effectiveness of brief interventions with substance using adolescents by type of drug. Drug and Alcohol Review 2003;22:337‐46.

Tevyaw 2004

Tevyaw TO'L, Monti PM. Motivational enhancement and other brief interventions for adolescent substance abuse: Foundations, applications, and evaluations. Addiction 2004;99:63‐75.

UNODC 2012

United Nations on Drugs, Crime. Cannabis: a short review. United Nations on Drugs and Crime; 2012. Youth Report.

Ward 2007

Ward CL, Martin E, Theron C, Distiller GB. Factors affecting resilience in children exposed to violence. South African Journal of Psychology 2007;37(1):165‐87.

Watchel 2010

Watchel T, Staniford M. The effectiveness of brief interventions in the clinical setting in reducing alcohol misuse and binge drinking in adolescents: a critical review of the literature. Journal of Clinical Nursing 2010;19:605‐20.

White 2012

White V, Bariola E. Australian secondary school students’ use of tobacco, alcohol, and over‐the‐counter and illicit substances in 2011. Victoria, Australia: Drug Strategy Branch Australian Government, Department of Health and Ageing; December 2012..

Winters 2007a

Winters KC, Leitten W, Wagner E, O’Leary Tevyaw T. Use of brief interventions for drug abusing teenagers within a middle and high school setting. Journal of School Health 2007;77(4):196‐206.

Winters 2008

Winters KC, Lee CS. Likelihood of developing an alcohol and cannabis use disorder during youth: association with recent use and age. Drug and Alcohol Dependence 2008;92:239‐47.

Young 2012

Young MM, Stevens A, Porath‐Waller A, Pirie T, Garritty C, Skidmore B, et al. Effectiveness of brief interventions as part of the screening, brief intervention and referral to treatment (SBIRT) model for reducing the non‐medical use of psychoactive substances: a systematic review protocol. Systematic Reviews 2012;1(22):1‐11.

References to other published versions of this review

Carney 2014

Carney T, Myers BJ, Louw J, Okwundu CI. Brief school‐based interventions and behavioural outcomes for substance‐using adolescents. Cochrane Database of Systematic Reviews 2014, Issue 2. [DOI: 10.1002/14651858.CD008969.pub2]

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Jump to:

McCambridge 2004

Methods

Cluster‐randomised controlled trial

Participants

Number of participants: 179

City and country: London, England

Type of setting: Urban

School setting: Alternative campus (further education training)

Gender: 46% female, 54% male

Mean age: 18.0 years

Inclusion criteria: 16 or older, attending FET, weekly or more use of cannabis

Exclusion criteria: Younger than 16, older than 19; less than weekly use cannabis; literacy (low levels); not English speaking

Interventions

Number of adolescents allocated to each group: 97 allocated to experimental condition, 82 allocated to control condition

Brief intervention: Motivational intervention versus information and advice‐giving

Dosage: 1 session

Type of delivery: Face‐to‐face (individual)

Timing: 1 hour

Outcomes

Follow‐up at 3 months and 12 months (2005 study)

Measures: Severity of Dependence Scale, The Drug Attitudes Scale

Primary outcomes:

  1. Frequency cannabis use

  2. Quantity cannabis use

  3. Cannabis use mean dependence score

  4. Frequency alcohol use

  5. Quantity alcohol use

  6. Alcohol use mean dependence score

  7. Frequency alcohol use

  8. Quantity alcohol use

  9. Alcohol use mean dependence score

  10. Quantity methamphetamine tablets used

Secondary outcomes:

  1. Cannabis‐Interactional Problems score

  2. Cannabis Problems score

  3. Alcohol‐Interactional Problems score

Notes

Only alcohol, cannabis frequency outcomes were measured at 12 months' follow‐up

Funding: Action on Addiction for 12 12 months' follow‐up assessments.

Conflict of interest: Information not reported

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Randomisation was non‐computerised and consisted of a colleague not involved in the study allocating clusters randomly to either the intervention or control condition. Stratification by college was applied in order to control for local variations in drug use

Allocation concealment (selection bias)

Low risk

Complete concealment was mentioned by the authors

Blinding of participants and personnel (performance bias)
All outcomes

High risk

Blinding is not possible for the type of intervention

Blinding of outcome assessment (detection bias)
All outcomes

Low risk

As 1 interventionist was the study principal investigator, a second independent interviewer who was blind to study condition was employed to conduct 3 months' follow‐ups, and an additional interviewer who was blind to initial group allocation was employed for 12 months' follow‐ups

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Attrition analyses conducted, and no difference was found between groups. Various factors associated with attrition in both groups were identified and controlled for in the analysis. In addition, follow‐up rates were provided for 3 months' follow‐up (experimental group: 92.4%; control group: 86.3%) and 12 months' follow‐up (experimental group: 80%; control group: 82%)

Selective reporting (reporting bias)

High risk

All outcomes discussed and reported on at 3 months' follow‐up, although at 12 months' follow‐up there was some unplanned deterioration of the intervention effect, so certain outcomes were not reported on

Other bias

Low risk

No other sources of bias identified

McCambridge 2008

Methods

Randomised controlled trial

Participants

Number of participants: 326

City and country: Inner London, England

Type of setting: Urban

School setting: Alternative campus (further education training)

Gender: 69% female, 31% male

Mean age: 18.0 years

Inclusion criteria: 16 or older, attending FET, weekly or more use of cannabis

Exclusion criteria: Younger than 16, older than 19; less than weekly use cannabis; literacy (low levels); not English speaking

Interventions

Number of adolescents allocated to each group: 164 to experimental group, 162 to control group

Brief intervention: Motivational intervention versus information and advice‐giving

Dosage: 1 session

Type of delivery: Face‐to‐face (individual)

Timing: 1 hour

Outcomes

Follow‐up at 3 months

Measures: Severity of Dependence Scale, Cannabis Problems Questionnaire, Alcohol Use Disorders Identification (AUDIT), Fagerström Test

Primary outcomes:

  1. Prevalence cannabis use

  2. Frequency cannabis use

  3. Quantity cannabis use

  4. Cannabis use mean dependence score

  5. Prevalence tobacco use

  6. Prevalence alcohol use

  7. Frequency alcohol use

  8. Quantity alcohol use

  9. Alcohol use mean dependence score

  10. Frequency alcohol use

  11. Quantity alcohol use

  12. Alcohol use mean dependence score

Secondary outcomes:

  1. Cannabis‐Interactional Problems score

  2. Cannabis Problems score

  3. Alcohol‐Interactional Problems score

Notes

Funding: Wellcome Trust for a Health Services Research Fellowship (071301), the Big Lottery Fund, and Action on Addiction

Conflict of interest: Information not reported

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computerised individual randomisation was undertaken by the local clinical trials unit, stratifying by college

Allocation concealment (selection bias)

Low risk

Recruitment and baseline data collection took place first, and then individual researchers were informed by telephone or e‐mail about selection to preserve allocation concealment

Blinding of participants and personnel (performance bias)
All outcomes

High risk

Blinding is not possible for the type of intervention

Blinding of outcome assessment (detection bias)
All outcomes

Low risk

Assessors were blind to the study conditions

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Attrition analyses were conducted, and there were no differences between groups in attrition or follow‐up rates ( experimental group: 85% at 3 months' follow‐up, 83% at 6 months' follow‐up; control group: 80% at 3 months' follow‐up, 80% at 6 months' follow‐up). Various factors associated with attrition were identified in both groups and controlled for in the analysis

Selective reporting (reporting bias)

Low risk

All outcomes discussed, attrition and differences in practitioner effects were also addressed

Other bias

Low risk

None reported

Walker 2011

Methods

Randomised controlled trial

Participants

Number of participants: 205

City and country: Seattle, Washington, USA

Type of setting: Urban

School setting: Alternative campus (further education training)

Gender: 69% female, 31% male

Mean age: 18.0 years

Inclusion criteria: 16 or older, attending FET, weekly or more use of cannabis

Exclusion criteria: Younger than 16, older than 19; less than weekly use cannabis; literacy (low levels); not English speaking

Interventions

Number of adolescents allocated to each group: 103 to experimental group, 102 to control group

Brief intervention: Motivational Enhancement Therapy versus information and advice‐giving

Dosage: 2 sessions

Type of delivery: Face‐to‐face (individual)

Timing: 45 to 50 minutes

Outcomes

Follow‐up at 3 months and 12 months

Measures: Global Appraisal of Individual Needs‐I, Marijuana Problem Inventory

Primary outcomes:

  1. Frequency cannabis use

  2. Cannabis dependency symptoms

  3. Cannabis abuse symptoms

Secondary outcomes:

  1. Cannabis problems

Notes

Funding: National Institute on Drug Abuse (RO1DA014296)

Conflict of interest: Information not reported

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Randomisation was conducted using randomisation tables per school

Allocation concealment (selection bias)

Unclear risk

Information not provided

Blinding of participants and personnel (performance bias)
All outcomes

High risk

Blinding is not possible for the type of intervention

Blinding of outcome assessment (detection bias)
All outcomes

Unclear risk

This was not clearly discussed, and it was unknown who delivered the baseline and follow‐up appointments

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Attrition levels were low (experimental group: 85% at 3 months' follow‐up, 83% at 12 months' follow‐up; control group: 80% at 3 months' follow‐up, 80% at 12 months' follow‐up), and no difference was found between groups in attrition. While no differences were found in attrition across the treatment conditions, an intention‐to‐treat analysis was still conducted

Selective reporting (reporting bias)

Low risk

The focus of the intervention was cannabis‐related outcomes, therefore, while cannabis, alcohol, and other drug frequency and quantity measures were included to assess if there were any differences between treatment groups at baseline, only outcomes related to cannabis were provided postintervention

Other bias

Low risk

None reported

Werch 2005

Methods

Randomised controlled trial of experiment

Participants

Number of participants: 201

City and country: Northeast Florida, USA

Type of setting: Urban

School setting: Public high school

Gender: 39.4% female, 60.6% male

Mean age: 16.04 years

Inclusion criteria: Age 14 to 19, Grade 9 to 12, 9 or more days of cannabis use in past 30 days

Exclusion criteria: Not fluent in English, had thought disorder, refused to accept randomisation to a condition

Interventions

Number of adolescents allocated to each group: 100 to experimental group, 101 to control group

Brief intervention: Screening, one‐on‐one risk reduction consultations, tip sheets with key messages from consultation, provided individual feedback, prevention messages were linked to different kinds of alcohol versus minimal intervention control

Dosage: 1 session

Type of delivery: Face‐to‐face (individual)

Timing: School hours

Outcomes

Follow‐up at 4 months

Primary outcomes:

  1. Alcohol risk factors

  2. Alcohol frequency

  3. Alcohol quantity

  4. Alcohol heavy use

  5. Alcohol "chugging"

Notes

Funding: National Institute on Alcohol Abuse and Alcoholism (AA9283)

Conflict of interest: Information not reported

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Although the investigators discussed the random allocation of participants, this is not clearly explained

Allocation concealment (selection bias)

Unclear risk

Insufficient information provided

Blinding of participants and personnel (performance bias)
All outcomes

High risk

Blinding is not possible for the type of intervention

Blinding of outcome assessment (detection bias)
All outcomes

Unclear risk

Insufficient information provided

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Equal distribution among groups, intention‐to‐treat analysis not necessary. 15 (10%) participants in the experimental group and 16 (13.7%) of participants in the control group dropped out of the study

Selective reporting (reporting bias)

High risk

Results were not indicative of all outcomes

Other bias

Unclear risk

Unknown, as first author is no longer working in the field of adolescent health research

Winters 2007b

Methods

Randomised controlled trial

Participants

Number of participants: 53 (79 including adolescents' parents who also received intervention)

City and country: Minnesota, USA

Type of setting: Urban

School setting: Public junior/high school

Gender: 35% female, 65% male

Mean age: 15.5 years

Inclusion criteria: Age 13 to 17, meets diagnostic criteria for 1 or more substance abuse disorders, agrees to participation with parents

Exclusion criteria: referred to a treatment programme, meets diagnostic criteria for DSM‐IV substance use dependence, currently in treatment programme, reported acute psychiatric or medical problem/condition

Interventions

Number of adolescents allocated to each group: 26 to experimental group, 27 to control group (26 to parent experimental group, which is not relevant to the current review)

Brief intervention: Motivational interviewing style session 1: obtain information about adolescents' substance use and consequences, address willingness to change, look at goals with regards to abstinence, reduction; session 2: some focus on progress to reaching goal, barriers; parenting session: address substance use problem, parent attitudes and behaviours, monitoring and supervision, versus assessment only (control)

Dosage: 2 sessions adolescents, 1 session parents

Type of delivery: Face‐to‐face (individual)

Timing: 1 hour per session, after school hours

Outcomes

Follow‐up at 6 months

Measures: Adolescent Diagnostic Interview, Timeline Followback, Personal Consequences Scale, Treatment Services Review

Primary outcomes:

  1. Frequency alcohol use

  2. Frequency alcohol binge use

  3. Frequency drug use

Secondary outcomes:

  1. Personal Consequences Scale

Notes

Funding: Robert Wood Johnson Foundation (Grant 38324) and National Institute on Drug Abuse (K02DA15347)

Conflict of interest: Information not reported

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Random selection by computer random‐number generator, no differences in groups at baseline

Allocation concealment (selection bias)

High risk

No concealment from investigators, which could introduce selection bias

Blinding of participants and personnel (performance bias)
All outcomes

High risk

Blinding is not possible for the type of intervention

Blinding of outcome assessment (detection bias)
All outcomes

Unclear risk

It is unclear if the outcome assessment was blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

There was only 1 attrition case (out of 27) in the control group (3.7%)

Selective reporting (reporting bias)

Low risk

Published report contains all outcomes that were discussed

Other bias

Low risk

None reported

Winters 2012

Methods

Randomised controlled trial

Participants

Number of participants: (315 including adolescents' parents who also received intervention)

City and country: Minnesota, USA

Type of setting: Urban

School setting: Public junior/high school

Gender: 48% female, 52% male

Mean age: 16.3 years

Inclusion criteria: Age 13 to 17, meets diagnostic criteria for 1 or more substance abuse disorders, agrees to participation with parents

Exclusion criteria: referred to a treatment programme, meets diagnostic criteria for DSM‐IV substance use dependence, currently in treatment programme, reported acute psychiatric or medical problem/condition

Interventions

Number of adolescents allocated to each group: 136 allocated to experimental group, 56 allocated to control group (123 allocated to adolescent‐parent condition not relevant for this review)

Brief intervention: Motivational interviewing style session 1: obtain information about adolescents' substance use and consequences, address willingness to change, look at goals with regards to abstinence, reduction; session 2: some focus on progress to reaching goal, barriers; parenting session: address substance use problem, parent attitudes and behaviours, monitoring and supervision, versus assessment only (control)

Dosage: 2 sessions adolescents, 1 session parents

Type of delivery: Face‐to‐face (individual)

Timing: 1 hour per session, after school hours

Outcomes

Follow‐up at 6 months and 12 months (2014 study)

Measures: Adolescent Diagnostic Interview, Timeline Followback, Personal Consequences Scale, Treatment Services Review

Primary outcomes:

  1. Frequency alcohol use

  2. Frequency alcohol binge use

  3. Frequency drug use

  4. Cannabis dependence symptoms

  5. Cannabis abuse symptoms

Secondary outcomes:

  1. Personal Consequences Scale

Notes

Funding: National Institute on Health (DA017492, AA14866, K02‐DA15347, and P50‐DA027841)

Conflict of interest: Information not reported

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Random selection by computer random‐number generator

Allocation concealment (selection bias)

High risk

No concealment from investigators, which could introduce selection bias

Blinding of participants and personnel (performance bias)
All outcomes

High risk

Blinding is not possible for the type of intervention

Blinding of outcome assessment (detection bias)
All outcomes

Unclear risk

It is unclear if the outcome assessment was blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No difference in 6 months' follow‐up attrition, which was very low. The follow‐up rate for the experimental group was 98.5% and for the control group was 98.2%

Selective reporting (reporting bias)

Low risk

All outcomes were reported

Other bias

Low risk

None reported

DSM‐IV: Diagnostic and Statistical Manual of Mental Disorders, 4th Edition
FET: further education training

Characteristics of excluded studies [ordered by study ID]

Jump to:

Study

Reason for exclusion

Apsler 2006

Length of intervention

Armitage 2014

Brief intervention was not delivered face‐to‐face

Baer 1992

College based intervention

Barnett 2012

Included prevention, only general substance use outcomes

Bear 2008

Not school‐based

Cirillo 1998

Length of intervention

Conrod 2013

Not all participants used substances, focused on those at risk of substance use

D'Amico 2002

Prevention, not intervention

D'Amico 2013

Not school‐based

de Gee 2014

Not school‐based

Dennis 2004

Not school‐based

Doumas 2014

Web‐based intervention, not delivered face‐to‐face

Gray 2005

Quasi‐experimental study, no randomisation (a consideration if not enough randomised controlled trials were found)

Hecht 2003

Prevention, not early intervention

Marsden 2006

Target population were not all students, was not school‐based

Martin 2008

Not school‐based

Newbury‐Birch 2014

Feasibility study, no measure of intervention effect

Peleg 2001

Prevention, not early intervention

Saunders 2004

College‐based interventions

Sinha 2003

Age of target population, not school‐based

Spoth 2001

Target population were not only adolescents, intervention aimed at entire family

Srisurapanont 2007

Not school‐based

Thaker 2008

Prevention, not early intervention

Tubman 2002

Pilot study, no comparison group (no abstract included so full ‐text article required)

Wagner 2014

Brief treatment, more than 4 sessions

Werch 1999

Prevention, not early intervention

Werch 2010

Majority of students did not use any substances

Williams 2007

Target population were receiving substance use treatment, not school‐based

Wu 2003

Length of intervention, not school‐based

Data and analyses

Open in table viewer
Comparison 1. Brief intervention versus information provision

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Alcohol Frequency: number of alcohol days past 30 days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 1.1

Comparison 1 Brief intervention versus information provision, Outcome 1 Alcohol Frequency: number of alcohol days past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 1 Alcohol Frequency: number of alcohol days past 30 days.

1.1 Short‐term Follow up (1‐3 months)

1

269

Std. Mean Difference (IV, Random, 95% CI)

‐0.05 [‐0.29, 0.19]

1.2 Medium‐term Follow up (4‐6 months)

2

434

Std. Mean Difference (IV, Random, 95% CI)

‐0.01 [‐0.20, 0.18]

2 Alcohol Quantity: number of standard drinks in past 30 days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 1.2

Comparison 1 Brief intervention versus information provision, Outcome 2 Alcohol Quantity: number of standard drinks in past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 2 Alcohol Quantity: number of standard drinks in past 30 days.

2.1 Short‐term Follow up (1‐3 months)

1

269

Std. Mean Difference (IV, Random, 95% CI)

0.02 [‐0.22, 0.26]

2.2 Medium‐term Follow up (4‐6 months)

2

434

Std. Mean Difference (IV, Random, 95% CI)

‐0.14 [‐0.33, 0.05]

3 Cannabis Quantity: number of joints smoked in past 30 days Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 1.3

Comparison 1 Brief intervention versus information provision, Outcome 3 Cannabis Quantity: number of joints smoked in past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 3 Cannabis Quantity: number of joints smoked in past 30 days.

3.1 Short‐term Follow up (1‐3 months)

1

269

Std. Mean Difference (IV, Random, 95% CI)

0.0 [‐0.24, 0.24]

3.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

‐0.15 [‐0.39, 0.09]

4 Cannabis Mean Dependence Score Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 1.4

Comparison 1 Brief intervention versus information provision, Outcome 4 Cannabis Mean Dependence Score.

Comparison 1 Brief intervention versus information provision, Outcome 4 Cannabis Mean Dependence Score.

4.1 Short‐term Follow up (1‐3 months)

2

470

Std. Mean Difference (IV, Random, 95% CI)

‐0.09 [‐0.27, 0.09]

4.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

0.06 [‐0.18, 0.30]

4.3 Long‐term Follow up (7‐12 months)

1

186

Std. Mean Difference (IV, Random, 95% CI)

‐0.09 [‐0.38, 0.20]

5 Cannabis frequency: number of days smoked cannabis in past 30 days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 1.5

Comparison 1 Brief intervention versus information provision, Outcome 5 Cannabis frequency: number of days smoked cannabis in past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 5 Cannabis frequency: number of days smoked cannabis in past 30 days.

5.1 Short‐term Follow up (1‐3 months)

2

470

Std. Mean Difference (IV, Random, 95% CI)

‐0.07 [‐0.25, 0.11]

5.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

‐0.06 [‐0.30, 0.18]

5.3 Long‐term Follow up (7‐12 months)

1

186

Std. Mean Difference (IV, Random, 95% CI)

‐0.02 [‐0.31, 0.26]

6 Secondary outcomes related to substance use: Mean Problem Score Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 1.6

Comparison 1 Brief intervention versus information provision, Outcome 6 Secondary outcomes related to substance use: Mean Problem Score.

Comparison 1 Brief intervention versus information provision, Outcome 6 Secondary outcomes related to substance use: Mean Problem Score.

6.1 Short‐term Follow up (1‐3 months)

2

470

Std. Mean Difference (IV, Random, 95% CI)

‐0.01 [‐0.19, 0.17]

6.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

‐0.13 [‐0.37, 0.11]

6.3 Long‐term Follow up (7‐12 months)

1

186

Std. Mean Difference (IV, Random, 95% CI)

‐0.10 [‐0.39, 0.19]

Open in table viewer
Comparison 2. Brief intervention versus assessment only

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Alcohol Frequency: number of alcohol days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.1

Comparison 2 Brief intervention versus assessment only, Outcome 1 Alcohol Frequency: number of alcohol days.

Comparison 2 Brief intervention versus assessment only, Outcome 1 Alcohol Frequency: number of alcohol days.

1.1 Medium‐term Follow up (4‐6 months)

2

242

Std. Mean Difference (IV, Random, 95% CI)

‐0.91 [‐1.21, ‐0.61]

1.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.20 [‐0.53, 0.14]

2 Alcohol Quantity: number of standard drinks Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.2

Comparison 2 Brief intervention versus assessment only, Outcome 2 Alcohol Quantity: number of standard drinks.

Comparison 2 Brief intervention versus assessment only, Outcome 2 Alcohol Quantity: number of standard drinks.

2.1 Medium‐term Follow up (4‐6 months)

1

179

Std. Mean Difference (IV, Random, 95% CI)

‐0.16 [‐0.45, 0.14]

2.2 Long‐term Follow up (7‐12 months)

1

162

Std. Mean Difference (IV, Random, 95% CI)

‐0.16 [‐0.47, 0.15]

3 Alcohol Abuse: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.3

Comparison 2 Brief intervention versus assessment only, Outcome 3 Alcohol Abuse: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 3 Alcohol Abuse: number of symptoms.

3.1 Medium‐term Follow up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.38 [‐0.70, ‐0.07]

3.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.72 [‐1.07, ‐0.38]

4 Alcohol Dependence: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.4

Comparison 2 Brief intervention versus assessment only, Outcome 4 Alcohol Dependence: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 4 Alcohol Dependence: number of symptoms.

4.1 Medium‐term Follow Up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.58 [‐0.90, ‐0.26]

4.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.13 [‐0.47, 0.20]

5 Cannabis frequency: number of cannabis use days Show forest plot

3

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.5

Comparison 2 Brief intervention versus assessment only, Outcome 5 Cannabis frequency: number of cannabis use days.

Comparison 2 Brief intervention versus assessment only, Outcome 5 Cannabis frequency: number of cannabis use days.

5.1 Short‐term Follow up (1‐3 months)

1

179

Std. Mean Difference (IV, Random, 95% CI)

‐0.83 [‐1.14, ‐0.53]

5.2 Medium‐term Follow up (4‐6 months)

2

242

Std. Mean Difference (IV, Random, 95% CI)

‐0.23 [‐0.50, 0.05]

5.3 Long‐term Follow up (7‐12 months)

2

338

Std. Mean Difference (IV, Random, 95% CI)

‐0.54 [‐0.77, ‐0.31]

6 Cannabis Abuse: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.6

Comparison 2 Brief intervention versus assessment only, Outcome 6 Cannabis Abuse: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 6 Cannabis Abuse: number of symptoms.

6.1 Medium‐term Follow up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.34 [‐0.65, ‐0.02]

6.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.62 [‐0.96, ‐0.28]

7 Cannabis Dependence: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.7

Comparison 2 Brief intervention versus assessment only, Outcome 7 Cannabis Dependence: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 7 Cannabis Dependence: number of symptoms.

7.1 Medium‐term Follow up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.26 [‐0.57, 0.06]

7.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.97 [‐1.32, ‐0.62]

8 Secondary outcomes related to substance use: Mean score on personal consequences scale Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

Analysis 2.8

Comparison 2 Brief intervention versus assessment only, Outcome 8 Secondary outcomes related to substance use: Mean score on personal consequences scale.

Comparison 2 Brief intervention versus assessment only, Outcome 8 Secondary outcomes related to substance use: Mean score on personal consequences scale.

8.1 Medium‐term Follow up (4‐6 months)

2

242

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.58, 0.28]

8.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.78 [‐1.13, ‐0.44]

Study flow diagram Carney 2014.
Figures and Tables -
Figure 1

Study flow diagram Carney 2014.

Study flow diagram for updated review.
Figures and Tables -
Figure 2

Study flow diagram for updated review.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Figures and Tables -
Figure 3

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Figures and Tables -
Figure 4

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Comparison 1 Brief intervention versus information provision, Outcome 1 Alcohol Frequency: number of alcohol days past 30 days.
Figures and Tables -
Analysis 1.1

Comparison 1 Brief intervention versus information provision, Outcome 1 Alcohol Frequency: number of alcohol days past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 2 Alcohol Quantity: number of standard drinks in past 30 days.
Figures and Tables -
Analysis 1.2

Comparison 1 Brief intervention versus information provision, Outcome 2 Alcohol Quantity: number of standard drinks in past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 3 Cannabis Quantity: number of joints smoked in past 30 days.
Figures and Tables -
Analysis 1.3

Comparison 1 Brief intervention versus information provision, Outcome 3 Cannabis Quantity: number of joints smoked in past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 4 Cannabis Mean Dependence Score.
Figures and Tables -
Analysis 1.4

Comparison 1 Brief intervention versus information provision, Outcome 4 Cannabis Mean Dependence Score.

Comparison 1 Brief intervention versus information provision, Outcome 5 Cannabis frequency: number of days smoked cannabis in past 30 days.
Figures and Tables -
Analysis 1.5

Comparison 1 Brief intervention versus information provision, Outcome 5 Cannabis frequency: number of days smoked cannabis in past 30 days.

Comparison 1 Brief intervention versus information provision, Outcome 6 Secondary outcomes related to substance use: Mean Problem Score.
Figures and Tables -
Analysis 1.6

Comparison 1 Brief intervention versus information provision, Outcome 6 Secondary outcomes related to substance use: Mean Problem Score.

Comparison 2 Brief intervention versus assessment only, Outcome 1 Alcohol Frequency: number of alcohol days.
Figures and Tables -
Analysis 2.1

Comparison 2 Brief intervention versus assessment only, Outcome 1 Alcohol Frequency: number of alcohol days.

Comparison 2 Brief intervention versus assessment only, Outcome 2 Alcohol Quantity: number of standard drinks.
Figures and Tables -
Analysis 2.2

Comparison 2 Brief intervention versus assessment only, Outcome 2 Alcohol Quantity: number of standard drinks.

Comparison 2 Brief intervention versus assessment only, Outcome 3 Alcohol Abuse: number of symptoms.
Figures and Tables -
Analysis 2.3

Comparison 2 Brief intervention versus assessment only, Outcome 3 Alcohol Abuse: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 4 Alcohol Dependence: number of symptoms.
Figures and Tables -
Analysis 2.4

Comparison 2 Brief intervention versus assessment only, Outcome 4 Alcohol Dependence: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 5 Cannabis frequency: number of cannabis use days.
Figures and Tables -
Analysis 2.5

Comparison 2 Brief intervention versus assessment only, Outcome 5 Cannabis frequency: number of cannabis use days.

Comparison 2 Brief intervention versus assessment only, Outcome 6 Cannabis Abuse: number of symptoms.
Figures and Tables -
Analysis 2.6

Comparison 2 Brief intervention versus assessment only, Outcome 6 Cannabis Abuse: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 7 Cannabis Dependence: number of symptoms.
Figures and Tables -
Analysis 2.7

Comparison 2 Brief intervention versus assessment only, Outcome 7 Cannabis Dependence: number of symptoms.

Comparison 2 Brief intervention versus assessment only, Outcome 8 Secondary outcomes related to substance use: Mean score on personal consequences scale.
Figures and Tables -
Analysis 2.8

Comparison 2 Brief intervention versus assessment only, Outcome 8 Secondary outcomes related to substance use: Mean score on personal consequences scale.

Summary of findings for the main comparison. Brief intervention compared to information provision for substance‐using adolescents

Brief intervention compared to information provision for substance‐using adolescents

Patient or population: Substance‐using adolescents
Settings: High schools or further education training colleges
Intervention: Brief intervention
Comparison: Information provision

Outcomes

Illustrative comparative risks* (95% CI)

Estimate effect
(95% CI)

No of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Information provision

Brief intervention

Alcohol frequency
Self report questionnaires
Medium‐term follow‐up: 4 to 6 months

See comment

The standardised mean alcohol frequency in the intervention groups was 0.01 standard deviations lower
(0.20 lower to 0.18 higher)

SMD ‐0.01 (‐0.20 to 0.18)

434
(2 studies)

⊕⊕⊕⊝
moderate1

Number of days of alcohol use

Alcohol quantity
Self report questionnaires

Medium‐term follow‐up: 4 to 6 months

See comment

The standardised mean alcohol quantity in the intervention groups was 0.14 standard deviations lower
(0.33 lower to 0.05 higher)

SMD ‐0.14 (‐0.33 to 0.05)

434
(2 studies)

⊕⊕⊕⊝
moderate1

Number of standard alcohol units

Cannabis dependence
Self report questionnaires
Short‐term follow‐up: 1 to 3 months

See comment

The standardised mean cannabis dependence score in the intervention groups was 0.09 standard deviations lower

(0.27 lower to 0.09 higher)

SMD ‐0.09 (‐0.27 to 0.09)

470
(2 studies)

⊕⊕⊕⊝
moderate1

Mean dependence score

Cannabis frequency
Self report questionnaires
Short‐term follow‐up: 1 to 3 months

See comment

The mean cannabis frequency in the intervention groups was
0.07 standard deviations lower
(0.25 lower to 0.11 higher)

SMD ‐0.07 (‐0.25 to 0.11)

470
(2 studies)

⊕⊕⊕⊝
moderate1

Number of days cannabis use

Secondary outcomes related to substance use
Self report questionnaires

Short‐term follow‐up: 1 to 3 months

See comment

The mean behavioural outcomes related to substance use in the intervention groups was
‐0.01 standard deviations lower
(0.19 lower to 0.17 higher)

SMD ‐0.01 (‐0.19 to 0.17)

470
(2 studies)

⊕⊕⊕⊝
moderate1

Interactional Problems Score

*The basis for the assumed risk (e.g. the mean control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the estimate effect of the intervention (and its 95% CI). The estimate effects for certain outcomes were not estimable due to only one study assessing the specific outcome, or extremely high levels of heterogeneity making effects across studies difficult to compare.
CI: confidence interval; SMD: standardised mean difference

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

1Risk of bias (‐1): It was not possible to blind the participants in all of the included studies. There was also uncertainty in two of the studies about allocation concealment and blinding of outcome assessor (Walker 2011; Werch 2005).

Figures and Tables -
Summary of findings for the main comparison. Brief intervention compared to information provision for substance‐using adolescents
Summary of findings 2. Brief intervention compared to assessment only for substance‐using adolescents

Brief intervention compared to assessment only for substance‐using adolescents

Patient or population: Substance‐using adolescents
Settings: High schools or further education colleges
Intervention: Brief intervention
Comparison: Assessment only

Outcomes

Illustrative comparative risks* (95% CI)

Estimate effect
(95% CI)

No of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Assessment only

Brief intervention

Alcohol frequency

Self report questionnaires
Medium‐term follow‐up: 4 to 6 months

See comment

The standardised mean alcohol frequency in the intervention groups was 0.91 standard deviations lower
(1.21 lower to 0.61 lower)

SMD ‐0.91 (‐1.21 to ‐0.61)

242
(2 studies)

⊕⊕⊝⊝
low1, 2

Number of days of alcohol use

Alcohol quantity
Self report questionnaires

Medium‐term follow‐up: 4 to 6 months

See comment

The standardised mean alcohol quantity in the intervention groups was 0.16 standard deviations lower
(0.45 lower to 0.14 higher)

SMD ‐0.16

(‐0.45 to 0.14)

179

(1 study)

⊕⊕⊝⊝
low1,2

Number of standard alcohol units

Cannabis dependence
Self report questionnaires
Medium‐term follow‐up: 4 to 6 months

See comment

The mean cannabis dependence in the intervention groups was
0.56 standard deviations lower
(0.57 lower to 0.06 higher)

SMD ‐0.26 (‐0.57 to 0.36)

190
(1 study)

⊕⊕⊝⊝
low1, 2

Mean dependence score

Cannabis frequency
Self report questionnaires
Long‐term follow‐up: 7 to 12 months

See comment

The mean cannabis frequency in the intervention groups was
0.54 standard deviations lower
(0.77 lower to 0.31 higher)

SMD ‐0.54 (‐0.77 to ‐0.31)

338
(2 studies)

⊕⊕⊝⊝
low1,2

Number of days of cannabis use

Secondary outcomes related to substance use

Self report questionnaires

Medium‐term follow‐up: 4 to 6 months

See comment

The mean mean behavioural outcomes related to substance use in the intervention groups was
0.65 standard deviations lower
(1.58 lower to 0.28 higher)

SMD ‐0.65 (‐1.58 to 0.28)

242
(2 studies)

⊕⊕⊝⊝
low1, 2

Interactional Problems Score

*The basis for the assumed risk (e.g. the mean control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the estimate effect of the intervention (and its 95% CI). The estimate effects for certain outcomes were not estimable due to only one study assessing the specific outcome, or extremely high levels of heterogeneity making effects across studies difficult to compare.
CI: confidence interval; SMD: standardised mean difference

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

1Risk of bias (‐1): It was not possible to blind the participants in all of the included studies. There was no allocation concealment in two of the included studies, and it was unclear whether the outcome assessor was blinded (Winters 2007b; Winters 2012). The other study was also not free of selective reporting bias (McCambridge 2004).
2Imprecision (‐1): The confidence intervals contained the null value of zero and the upper or lower confidence limit crosses an effect size of 0.5 in either direction; the sample size was also small for medium‐term follow‐up.

Figures and Tables -
Summary of findings 2. Brief intervention compared to assessment only for substance‐using adolescents
Comparison 1. Brief intervention versus information provision

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Alcohol Frequency: number of alcohol days past 30 days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

1.1 Short‐term Follow up (1‐3 months)

1

269

Std. Mean Difference (IV, Random, 95% CI)

‐0.05 [‐0.29, 0.19]

1.2 Medium‐term Follow up (4‐6 months)

2

434

Std. Mean Difference (IV, Random, 95% CI)

‐0.01 [‐0.20, 0.18]

2 Alcohol Quantity: number of standard drinks in past 30 days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

2.1 Short‐term Follow up (1‐3 months)

1

269

Std. Mean Difference (IV, Random, 95% CI)

0.02 [‐0.22, 0.26]

2.2 Medium‐term Follow up (4‐6 months)

2

434

Std. Mean Difference (IV, Random, 95% CI)

‐0.14 [‐0.33, 0.05]

3 Cannabis Quantity: number of joints smoked in past 30 days Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

3.1 Short‐term Follow up (1‐3 months)

1

269

Std. Mean Difference (IV, Random, 95% CI)

0.0 [‐0.24, 0.24]

3.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

‐0.15 [‐0.39, 0.09]

4 Cannabis Mean Dependence Score Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

4.1 Short‐term Follow up (1‐3 months)

2

470

Std. Mean Difference (IV, Random, 95% CI)

‐0.09 [‐0.27, 0.09]

4.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

0.06 [‐0.18, 0.30]

4.3 Long‐term Follow up (7‐12 months)

1

186

Std. Mean Difference (IV, Random, 95% CI)

‐0.09 [‐0.38, 0.20]

5 Cannabis frequency: number of days smoked cannabis in past 30 days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

5.1 Short‐term Follow up (1‐3 months)

2

470

Std. Mean Difference (IV, Random, 95% CI)

‐0.07 [‐0.25, 0.11]

5.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

‐0.06 [‐0.30, 0.18]

5.3 Long‐term Follow up (7‐12 months)

1

186

Std. Mean Difference (IV, Random, 95% CI)

‐0.02 [‐0.31, 0.26]

6 Secondary outcomes related to substance use: Mean Problem Score Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

6.1 Short‐term Follow up (1‐3 months)

2

470

Std. Mean Difference (IV, Random, 95% CI)

‐0.01 [‐0.19, 0.17]

6.2 Medium‐term Follow up (4‐6 months)

1

264

Std. Mean Difference (IV, Random, 95% CI)

‐0.13 [‐0.37, 0.11]

6.3 Long‐term Follow up (7‐12 months)

1

186

Std. Mean Difference (IV, Random, 95% CI)

‐0.10 [‐0.39, 0.19]

Figures and Tables -
Comparison 1. Brief intervention versus information provision
Comparison 2. Brief intervention versus assessment only

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Alcohol Frequency: number of alcohol days Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

1.1 Medium‐term Follow up (4‐6 months)

2

242

Std. Mean Difference (IV, Random, 95% CI)

‐0.91 [‐1.21, ‐0.61]

1.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.20 [‐0.53, 0.14]

2 Alcohol Quantity: number of standard drinks Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

2.1 Medium‐term Follow up (4‐6 months)

1

179

Std. Mean Difference (IV, Random, 95% CI)

‐0.16 [‐0.45, 0.14]

2.2 Long‐term Follow up (7‐12 months)

1

162

Std. Mean Difference (IV, Random, 95% CI)

‐0.16 [‐0.47, 0.15]

3 Alcohol Abuse: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

3.1 Medium‐term Follow up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.38 [‐0.70, ‐0.07]

3.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.72 [‐1.07, ‐0.38]

4 Alcohol Dependence: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

4.1 Medium‐term Follow Up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.58 [‐0.90, ‐0.26]

4.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.13 [‐0.47, 0.20]

5 Cannabis frequency: number of cannabis use days Show forest plot

3

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

5.1 Short‐term Follow up (1‐3 months)

1

179

Std. Mean Difference (IV, Random, 95% CI)

‐0.83 [‐1.14, ‐0.53]

5.2 Medium‐term Follow up (4‐6 months)

2

242

Std. Mean Difference (IV, Random, 95% CI)

‐0.23 [‐0.50, 0.05]

5.3 Long‐term Follow up (7‐12 months)

2

338

Std. Mean Difference (IV, Random, 95% CI)

‐0.54 [‐0.77, ‐0.31]

6 Cannabis Abuse: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

6.1 Medium‐term Follow up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.34 [‐0.65, ‐0.02]

6.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.62 [‐0.96, ‐0.28]

7 Cannabis Dependence: number of symptoms Show forest plot

1

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

7.1 Medium‐term Follow up (4‐6 months)

1

190

Std. Mean Difference (IV, Random, 95% CI)

‐0.26 [‐0.57, 0.06]

7.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.97 [‐1.32, ‐0.62]

8 Secondary outcomes related to substance use: Mean score on personal consequences scale Show forest plot

2

Std. Mean Difference (IV, Random, 95% CI)

Subtotals only

8.1 Medium‐term Follow up (4‐6 months)

2

242

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.58, 0.28]

8.2 Long‐term Follow up (7‐12 months)

1

170

Std. Mean Difference (IV, Random, 95% CI)

‐0.78 [‐1.13, ‐0.44]

Figures and Tables -
Comparison 2. Brief intervention versus assessment only