Epidemiological trends and risk factors for tobacco, alcohol and drug use among adolescents in Scotland, 2002-13.

Background: This study estimates trends in prevalence, and patterns, of individual and multiple substance use between 2002 and 2013 amongst adolescents in Scotland.

Methods: The study uses data from 134 387 participants of the biennial national 'Scottish Schools Adolescent Lifestyle and Substance Use Survey' on smoking, alcohol and illicit drug use. Current regular use and current heavy use of smoking, alcohol, illicit drugs and multiple substances was measured. Time trends in the prevalence of each outcome were estimated using univariate and multivariate logistic regression.

Results: Regular smoking, alcohol, illicit drug and multiple substance use declined significantly amongst adolescents in Scotland. However, multivariate analyses that focussed upon high-risk levels of these behaviours revealed an upward linear trend in heavy alcohol (OR = 1.06; 95% CI: 1.04, 1.07) and heavy illicit drug (OR = 1.04; 95% CI: 1.00, 1.08) use (P < 0.05). Non-white pupils were more likely to be involved in individual and multiple substance use than ethnically white British pupils. In comparison to pupils from the least deprived socioeconomic quintile, pupils from the most deprived quintile had increased odds of 1.41 (95% CI: 1.02, 1.97; P < 0.05) and 1.62 (95% CI: 1.14, 2.29; P < 0.05) of being regular and heavy multiple substance users, respectively.

Conclusions: Further effort is required to tackle heavy alcohol and heavy illicit drug use amongst adolescents in Scotland. Prevention strategies should be informed by the risk profiles of substance misusers and evidence around the clinical and cost-effectiveness of preventive interventions.