Systematic review of universal school-based 'resilience' interventions targeting adolescent tobacco, alcohol or illicit substance use: A meta-analysis.

Universal school-based interventions that address adolescent 'resilience' may represent a means of reducing adolescent substance use, however previous systematic reviews have not examined the effectiveness of such an intervention approach. A systematic review was undertaken to 1) assess whether universal school-based 'resilience' interventions are effective in reducing the prevalence of tobacco, alcohol or illicit substance use by adolescents, and 2) describe such effectiveness per intervention characteristic subgroups. Eligible studies were peer-reviewed reports (1994-2015) of randomised controlled trials including participants aged 5-18years that reported adolescent tobacco, alcohol or illicit substance use, and implemented a universal school-based 'resilience' intervention (i.e. those addressing both individual (e.g. self-esteem) and environmental (e.g. school connectedness) protective factors of resilience). Trial effects for binary outcomes were synthesised via meta-analyses and effect sizes reported as odds ratios. Subgroup (by intervention type, prevention approach, setting, intervention duration, follow-up length) and sensitivity analyses (excluding studies at high risk of bias) were conducted. Nineteen eligible studies were identified from 16,619 records (tobacco: n=15, alcohol: n=17, illicit: n=11). An overall intervention effect was found for binary measures of illicit substance use (n=10; OR: 0.78, 95%CI: 0.6-0.93, p=0.007,Tau2=0.0, I2=0%), but not tobacco or alcohol use. A similar result was found when studies assessed as high risk of bias were excluded. Overall intervention effects were evident for illicit substance use within multiple intervention characteristic subgroups, but not tobacco and alcohol. Such results support the implementation of universal school-based interventions that address 'resilience' protective factors to reduce adolescent illicit substance use, however suggest alternate approaches are required for tobacco and alcohol use. PROSPERO registration: CRD42014004906.