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Brief school-based interventions and behavioural outcomes for substance-using adolescents

  1. Tara Carney1,*,
  2. Bronwyn J Myers1,2,
  3. Johann Louw3,
  4. Charles I Okwundu4,5

Editorial Group: Cochrane Drugs and Alcohol Group

Published Online: 4 FEB 2014

Assessed as up-to-date: 20 NOV 2012

DOI: 10.1002/14651858.CD008969.pub2


How to Cite

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. Art. No.: CD008969. DOI: 10.1002/14651858.CD008969.pub2.

Author Information

  1. 1

    South African Medical Research Council, Alcohol and Drug Abuse Research Unit, Cape Town, Western Cape, South Africa

  2. 2

    University of Cape Town, Department of Psychiatry and Mental Health, Cape Town, South Africa

  3. 3

    University of Cape Town, Department of Psychology, Cape Town, Western Cape, South Africa

  4. 4

    Stellenbosch University, Centre for Evidence-based Health Care, Faculty of Medicine and Health Sciences, Tygerberg, South Africa

  5. 5

    South African Medical Research Council, South African Cochrane Centre, Tygerberg, Western Cape, South Africa

*Tara Carney, Alcohol and Drug Abuse Research Unit, South African Medical Research Council, Francie van Zyl Drive, Tygerberg, 7505, Parow, Cape Town, Western Cape, 7505, South Africa. tara.carney@mrc.ac.za.

Publication History

  1. Publication Status: New
  2. Published Online: 4 FEB 2014

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Characteristics of included studies [ordered by study ID]
McCambridge 2004

MethodsCluster-randomised controlled trial


ParticipantsNumber 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

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


InterventionsNumber of participants allocated to each group: 97 allocated to experimental condition, 82 allocated to control condition

Brief Intervention: Motivational intervention versus information and advice-giving

Dosage: one session

Type of Delivery: Face-to-face (individual)

Timing: One hour


OutcomesFollow-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


NotesOnly alcohol, tobacco, cannabis frequency outcomes were measured at 12 months follow-up.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskRandomisation 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 riskComplete concealment was mentioned by the authors

Blinding of outcome assessment (detection bias)
All outcomes
Low riskAs one interventionist was the study PI, a second independent interviewer who was blind to study condition was employed to conduct 3 month 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 riskAttrition analyses conducted and no difference found between groups in attrition. 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 month follow-up (experimental group: 92.4%, control group: 86.3%) and 12 month follow-up (experimental group: 80%, control group: 82%)

Selective reporting (reporting bias)High riskAll outcomes discussed and reported on at 3 month follow-up, although at 12 month follow-up there was some unplanned deterioration of the intervention effect so certain outcomes were not reported on

Other biasLow riskNo other sources of bias identified

McCambridge 2008

MethodsRandomised controlled trial


ParticipantsNumber 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.


InterventionsNumber of participants allocated to each group: 164 to experimental group, 162 to control group

Brief Intervention: Motivational intervention versus information and advice-giving

Dosage: One session

Type of Delivery: Face-to-face (individual)

Timing: One hour


OutcomesFollow-up at 3 months

Measures: Severity of Dependence Scale, Cannabis Problems Questionnaire, Alcohol Use Disorders Identification (AUDIT), Fagerstrom 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) Frequency tobacco use

7) Quantity tobacco use

8) Tobacco use mean dependence score

9) Prevalence alcohol use

9) Frequency alcohol use

10) Quantity alcohol use

11) Alcohol use mean dependence score

12) Frequency alcohol use

13) Quantity alcohol use

14) Alcohol use mean dependence score

Secondary outcomes:

1) Cannabis-Interactional Problems score

2) Cannabis Problems score

3) Tobacco-Interactional Problems score

3) Alcohol-Interactional Problems score


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskComputerised individual randomisation was undertaken by the local clinical trials unit, stratifying by college

Allocation concealment (selection bias)Low riskRecruitment 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 outcome assessment (detection bias)
All outcomes
Low riskAssessors were blind to the study conditions

Incomplete outcome data (attrition bias)
All outcomes
Low riskAttrition analyses were conducted and there were no differences between groups in attrition or FU rates. (Experimental group: 85% at 3 month follow-up, 83% at 6 month follow-up; control group: 80% at 3 month follow-up, 80% at 6 month follow-up). Various factors associated with attrition were identified in both groups and controlled for in the analysis

Selective reporting (reporting bias)Low riskAll outcomes discussed, attrition and differences in practitioner effects were also addressed

Other biasLow riskNone reported

Walker 2011

MethodsRandomised controlled trial


ParticipantsNumber 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


InterventionsNumber of participants allocated to each group: 103 to experimental group, 102 to control group

Brief Intervention: Motivational Enhancement Therapy versus information and advice-giving

Dosage: Two sessions

Type of Delivery: Face-to-face (individual)

Timing: 45 to 50 minutes


OutcomesFollow-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


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskRandomisation was conducted using randomisation tables per school

Allocation concealment (selection bias)Unclear riskInformation not provided

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskThis was not clearly discussed, and it was unknown who delivered the baseline and follow-up appointments

Incomplete outcome data (attrition bias)
All outcomes
Low riskAttrition levels were low (experimental group: 85% at 3 month follow-up, 83% at 12 month follow-up; control group: 80% at 3 month follow-up, 80% at 12 month follow-up), and no difference 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 riskThe focus of the intervention was only on 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 group at baseline, only outcomes related to cannabis were provided post-intervention

Other biasLow riskNone reported

Werch 2005

MethodsRandomised controlled trial of experiment


ParticipantsNumber of participants: 201

City and Country: North East 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 14-19, Grade 9-12, 9 or more days of cannabis use in past 30 days

Exclusion Criteria: were not fluent in English, had though disorder, refused to accept randomisation to a condition


InterventionsNumber of participants 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: One session

Type of Delivery: Face-to-face (individual)

Timing: School hours


OutcomesFollow-up at 4 months

Primary outcomes:

1) Alcohol risk factors

2) Alcohol frequency

3) Alcohol quantity

4) Alcohol heavy use

5) Alcohol "chugging"


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskAlthough the investigators discussed the random allocation of participants, this is not clearly explained

Allocation concealment (selection bias)Unclear riskInsufficient information provided

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskInsufficient information provided

Incomplete outcome data (attrition bias)
All outcomes
Low riskEqual distribution among groups, not intention-to-treat analysis necessary. There were 15 (10%) participants in the experimental group, and 16 (13.7%) of participants in the control group who dropped out of the study

Selective reporting (reporting bias)High riskResults were not indicative of all outcomes

Other biasUnclear riskUnknown as first author is no longer working in the field of adolescent health research

Winters 2007b

MethodsRandomised controlled trial


ParticipantsNumber of participants: 53 (79 including adolescents whose parents 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 13-17, meet diagnostic criteria for one or more substance abuse disorder, agree to participation with parents

Exclusion Criteria: If students were referred to a treatment programme, met diagnostic criteria for DSM-IV substance use dependence, currently in treatment programme, reported acute psychiatric or medical problem/condition


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

Brief Intervention: Motivational interviewing style session 1: information obtained about students' 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: addressed substance use problem, parent attitudes and behaviours, monitoring and supervision versus assessment only (control)

Dosage: Two sessions adolescents, one session parents

Type of Delivery: Face-to-face (individual)

Timing: One hour per session, after school hours


OutcomesFollow-up at six months

Measures: Adolescent Diagnostic Interview, Timeline follow back, 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


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskRandom selection by computer random number generator, no differences in groups at baseline

Allocation concealment (selection bias)High riskNo concealment from investigators, which could introduce selection bias

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskIt is unclear if the outcome assessment was blinded

Incomplete outcome data (attrition bias)
All outcomes
Low riskThere was only one attrition case (out of 27) in the control group (3.7%)

Selective reporting (reporting bias)Low riskPublished report contains all outcomes that were discussed

Other biasLow riskNone reported

Winters 2012

MethodsRandomised controlled trial


ParticipantsNumber of participants: (315 including adolescents whose parents 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 13-17, meet diagnostic criteria for one or more substance abuse disorder, agree to participation with parents

Exclusion Criteria: If students were referred to a treatment programme, met diagnostic criteria for DSM-IV substance use dependence, currently in treatment programme, reported acute psychiatric or medical problem/condition


InterventionsNumber of participants 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: information obtained about students' 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: addressed substance use problem, parent attitudes and behaviours, monitoring and supervision versus assessment only (control)

Dosage: Two sessions adolescents, one session parents

Type of Delivery: Face-to-face (individual)

Timing: One hour per session, after school hours


OutcomesFollow up at six months

Measures: Adolescent Diagnostic Interview, Timeline follow back, 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


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskRandom selection by computer random number generator

Allocation concealment (selection bias)High riskNo concealment from investigators which could introduce selection bias

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskIt is unclear if the outcome assessment was blinded

Incomplete outcome data (attrition bias)
All outcomes
Low riskNo difference in 6 month follow-up attrition, which were very low. The follow-up rate for the experimental group was 98.5% and for the control group it was 98.2%

Selective reporting (reporting bias)Low riskAll absolute and mediation outcomes were reported on

Other biasLow riskNone reported

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Apsler 2006Length of intervention

Baer 1992College based intervention

Barnett 2012Included prevention, only general substance use outcomes

Bear 2008Not school-based

Cirillo 1998Length of intervention

D'Amico 2002Prevention, not intervention

Dennis 2004Not school-based

Gray 2005Quasi-experimental study, no randomisation

Hecht 2003Prevention, not early intervention

Marsden 2006Target population were not all students, was not school-based

Martin 2008Not school-based

Peleg 2001Prevention, not early intervention

Saunders 2004College-based interventions

Sinha 2003Age of target population, not school-based

Spoth 2001Target population were not only adolescents, intervention aimed at entire family

Srisurapanont 2007Not school-based

Thaker 2008Prevention, not early intervention

Tubman 2002Pilot study, no comparison group

Turner 1998Survey, no intervention provided

Werch 1999Prevention, not early intervention

Werch 2010Majority of students did not use any substances

Williams 2007Target population were receiving substance use treatment, not school-based

Wu 2003Length of intervention, not school-based

 
Comparison 1. Brief intervention versus information provision

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Any substance use outcomes3732Std. Mean Difference (IV, Random, 95% CI)-0.06 [-0.20, 0.09]

 2 Alcohol Frequency2527Std. Mean Difference (IV, Random, 95% CI)-0.03 [-0.20, 0.14]

 3 Alcohol Quantity2527Std. Mean Difference (IV, Random, 95% CI)-0.09 [-0.26, 0.08]

 4 Tobacco frequency1Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 5 Cannabis Quantity1Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 6 Cannabis Dependence2531Std. Mean Difference (IV, Random, 95% CI)-0.03 [-0.20, 0.14]

 7 Cannabis frequency2531Std. Mean Difference (IV, Random, 95% CI)-0.02 [-0.19, 0.15]

 8 All behavioural outcomes2531Std. Mean Difference (IV, Random, 95% CI)-0.26 [-0.54, 0.02]

 
Comparison 2. Brief intervention versus assessment only

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Any substance use outcomes3Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 2 Alcohol Frequency3Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 3 Alcohol Quantity1Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 4 Tobacco frequency1Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 5 Cannabis frequency3407Std. Mean Difference (IV, Random, 95% CI)-0.22 [-0.43, -0.02]

 6 Cannabis Quantity1Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 7 Cannabis Dependence1Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 8 All behavioural outcomes2Std. Mean Difference (IV, Random, 95% CI)Totals not selected

 
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

OutcomesIllustrative comparative risks* (95% CI)Estimate effect
(95% CI)
No of Participants
(studies)
Quality of the evidence
(GRADE)
Comments

Assumed riskCorresponding risk

Information provisionBrief intervention

General substance use outcomes
Self-Report Questionnaires
Follow-up: mean 1-12 months
The standardised mean substance use outcomes in the intervention groups was
0.06 standard deviations lower
(0.20 lower to 0.09 higher)
SMD -0.06 (-0.20 t0 0.09)732
(3 studies)
⊕⊕⊕⊝
moderate1
Included both alcohol and drug use outcomes

Alcohol frequency
Self-Report Questionnaires
Follow-up: mean 1-12 months
The standardised mean alcohol frequency in the intervention groups was 0.03 standard deviations lower
(0.20 lower to 0.14 higher)
SMD -0.03 (-0.20 t0 0.14)527
(2 studies)
⊕⊕⊕⊝
moderate1
Number of days of alcohol use

Alcohol quantity
Self-Report Questionnaires
Follow-up: mean 1-12 months
The standardised mean alcohol quantity in the intervention groups was 0.09 standard deviations lower
(0.26 lower to 0.08 higher)
SMD -0.09 (-0.26 to 0.08)527
(2 studies)
⊕⊕⊕⊝
moderate1
Number of standard alcohol units

Tobacco frequency
Self-Report Questionnaires
Follow-up: mean 6 months
See commentSee commentNot estimable326
(1 study)
⊕⊕⊕⊝
moderate1
Number of days cigarettes used

Cannabis quantity
Self-Report Questionnaires
Follow-up: mean 6 months
See commentSee commentNot estimable326
(1 study)
⊕⊕⊕⊝
moderate1
Number of joints (cannabis cigarettes)

Cannabis frequency
Self-Report Questionnaires
Follow-up: mean 6-12 weeks
The mean cannabis frequency in the intervention groups was
0.02 standard deviations lower
(0.19 lower to 0.15 higher)
SMD -0.02 (-0.19 to 0.15)531
(2 studies)
⊕⊕⊕⊝
moderate1
Number of days cannabis use

All behavioural outcomes
Self-Report Questionnaires
The mean all behavioural outcomes in the intervention groups was
0.26 standard deviations lower
(0.54 lower to 0.02 higher)
SMD -0.26 (-0.54 to 0.02)531
(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

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.

 1 Risk of bias (-1): In two of the three studies, there was uncertainty about the risk of bias
2 Imprecision (-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
 
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

OutcomesIllustrative comparative risks* (95% CI)Estimate effect
(95% CI)
No of Participants
(studies)
Quality of the evidence
(GRADE)
Comments

Assumed riskCorresponding risk

Assessment onlyBrief intervention

General substance use outcomesSee commentSee commentNot estimable407
(3 studies)
⊕⊕⊕⊝
moderate1
Included both alcohol and drug use outcomes

Alcohol frequencySee commentSee commentNot estimable407
(3 studies)
⊕⊕⊝⊝
low1, 2
Number of days of alcohol use

Alcohol quantitySee commentNot estimable179
(1 study)
⊕⊕⊝⊝
low2, 3
Number of standard alcohol units

Tobacco frequencySee commentSMD -0.03 (-0.61 to 0.01)162
(1 study)
⊕⊕⊝⊝
low2, 3
Number of days cigarettes used

Cannabis frequencyThe mean cannabis frequency in the intervention groups was
0.22 standard deviations lower
(0.43 lower to 0.02 higher)
SMD -0.22 (-0.43 to 0.02)407
(3 studies)
⊕⊕⊝⊝
low1, 3
Number of joints (cannabis cigarettes)

Cannabis quantitySee commentNot estimable179
(1 study)
⊕⊕⊝⊝
low2, 3
Number of days cannabis use

All behavioural outcomesSee commentSee commentNot estimable245
(2 studies)
⊕⊝⊝⊝
very low1, 2, 5
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

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.

 1 Risk of bias (-1): There was no allocation concealment in the study
2 Imprecision (-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
3 Risk of bias (-1): The study was not free of selective outcome reporting
4 Risk of bias (-1): There was no allocation concealment in two of the studies
5 Inconsistency (-1): There was a significant amount of unexplained heterogeneity across the two studies (P < 0.05)