Consistent predictors of adolescent substance use: cross-sectional comparison across five countries

Background Adolescent substance use differs across cultures, but the key drivers may be shared. We examined whether country of residence, psychological distress, adverse childhood experiences (ACEs), and Big Five personality traits are associated with alcohol and drug use, and whether these associations vary by country. Methods We conducted a cross-sectional online survey of 5,108 upper-secondary students aged 15–19 from the United States, Sweden, Serbia, Morocco, and Vietnam. Outcomes were scores on the Alcohol Use Disorders Identification Test (AUDIT) and the Drug Use Disorders Identification Test (DUDIT). Predictors included country, age, gender, psychological distress, four ACEs (family alcohol problems, family drug problems, physical abuse, psychological abuse), and Big Five traits. Results Alcohol use was higher in Sweden and Serbia and lower in Morocco and Vietnam compared with the United States. Drug use was highest in the United States and lower in all other countries (lowest in Vietnam and Serbia). Older age predicted higher AUDIT and DUDIT scores. Gender was unrelated to alcohol use, whereas drug use was highest among young men. Psychological distress showed the strongest positive association with both outcomes. For alcohol, family alcohol and family drug problems predicted higher use; physical and psychological abuse were not significant. For drugs, family drug problems and experiences of physical and psychological abuse predicted higher use; family alcohol problems did not. Personality effects were consistent: extraversion predicted higher use, whereas conscientiousness, agreeableness, openness, and—more modestly for alcohol—neuroticism predicted lower use. Associations were largely stable across countries. Conclusion While levels of alcohol and drug use differ across countries, the core predictors are consistent: psychological distress and early adversity elevate risk, whereas conscientiousness and agreeableness are protective and extraversion signals vulnerability. Prevention efforts should combine trauma-informed, mental-health approaches with personality-targeted programs. Limitations include uneven country distributions and pandemic timing.