title: Long-term impact of the Gatehouse Project on cannabis use of 16-year-olds in Australia.
abstract: This study examined the impact of a school-based preventive intervention on cannabis use in adolescence, using a cluster-randomized trial of a multilevel intervention aimed at improving social relationships within schools by promoting change in school environment. Four waves of data were collected at baseline (1997, Year 8: mean age 13 years) and six, 18, and 30 months later (1999, Year 10: mean age 16 years). Self-reported substance use, school engagement, and sociodemographic data were collected using computer-administered questionnaires. Some 2.678(74%) Year 8 students participated (wave 1) with minimal attrition (10% by wave 4). Adjusting for baseline use, weak evidence existed for an intervention effect on the prevalence of any use at Year 10 (OR 0.75, 95% CI 0.54, 1.05) and incident weekly use (OR 0.72, 95% CI 0.39, 1.33). These effects were reduced after adjusting for confounders. Moderate evidence suggested an interaction effect between intervention group and tobacco use (p = 0.04), suggesting the intervention was more effective for non-smokers at baseline (Adj. OR 0.50, 95% CI 0.26, 0.98). This study indicates that a multi-level school-based program may provide an innovative direction for sustainable school interventions with the potential to reduce substance use.
authors.affiliation: Centre for Adolescent Health, 2 Gatehouse St., Parkville 3052, Victoria, Australia. lyndal.bond@rch.org.au
authors.forename: Lyndal
authors.initials: L
authors.lastname: Bond
authors.forename: Lyndal
authors.initials: L
authors.lastname: Thomas
authors.forename: Carolyn
authors.initials: C
authors.lastname: Coffey
authors.forename: Sara
authors.initials: S
authors.lastname: Glover
authors.forename: Helen
authors.initials: H
authors.lastname: Butler
authors.forename: John B
authors.initials: JB
authors.lastname: Carlin
authors.forename: George
authors.initials: G
authors.lastname: Patton
mesh_terms: D000293:Adolescent; D001315:Australia / Q000453:epidemiology; D015986:Confounding Factors, Epidemiologic; D005260:Female; D015438:Health Behavior; D006266:Health Education / Q000458:organization & administration; D006293:Health Promotion / Q000458:organization & administration*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology / Q000517:prevention & control*; D015995:Prevalence; D011322:Primary Prevention / Q000458:organization & administration*; D015397:Program Evaluation; D012572:School Health Services / Q000458:organization & administration*; D012931:Social Environment; D011795:Surveys and Questionnaires; D014505:Urban Population