Substance-general and substance-specific influences on adolescent vaping, smoking, alcohol consumption, and illicit drug use: context, inequalities, and determinants

Background: Using substances before the age of 15 is a key risk for requiring substance usetreatment later in life. Since the turn of the 21st century, adolescents' lives have changedconsiderably, potentially creating new patterns of risk and protection. Identifying determinantfactors and contexts associated with specific substances among contemporary adolescents istherefore a key public health priority. Methods: We investigated vaping, smoking, alcohol consumption, and illicit drug use, in30,920 adolescents aged 12-15 attending 100 schools and living across 1,539 neighbourhoodsin the south of England. Cross-classified multi-level models were used to evaluate the relativeimportance of school and neighbourhood contexts, before investigating determinants ofsubstance use. Results: The school-only context yielded the best model fit and explained the most varianceacross substances (ICC range 6% to 8.4%). Several patterns pertaining to inequalities insubstance use emerged (e.g., increased age associated with amplified odds of any substanceuse, particularly illicit drugs), although the magnitude and direction of associations varied bysubstance and subgroup. Findings emphasised the importance of coping motives (e.g.,internalising symptoms) as potential risk factors for vaping, smoking, and alcoholconsumption. Strong parental and teacher relationships and school-based factors (e.g., strongsense of school belonging) were protective against all substances. Conclusion: Differences between schools matter more than differences betweenneighbourhoods for adolescent substance use. Our results reveal both substance-general andsubstance-specific determinants, highlighting the need for tailored approaches that targetshared and unique drivers of use. Such strategies should also account for sociodemographicdifferences.