Introduction:
Recent research has called upon investigators to exploit cross-national differences to uncover the cultural and structural factors influencing drug use. While the individual-level correlates are well-established, little is known about the association between cross-national variation in drug policies and young people's substance use. This study examines, net of individual-level predictors, the association between national-level drug policy and use of an illicit drug other than cannabis.

Methods:
The study uses Eurobarometer repeated cross-sectional surveys in 2002 and 2004 of adolescents aged 15–24 drawn in multistage, random probability samples proportional to population size and density within regions of their country (N = 15,191). Participants completed self-reported measures of last month drug use, attitudes toward drugs, school and work participation, and demographics. Gathered from several international bodies, national-level policy measures include drug offense levels, possession decriminalization, and presence and usage of harm reduction strategies.

Results:
Hierarchical logistic regression models demonstrate that, while controlling for important individual-level predictors, in countries where there is no restriction on possession of drugs for personal use, the odds of drug use in the last month are 79% lower (p < 0.05). On the other hand, higher usage of treatment and drug substitution are associated with higher levels of drug use. These results are robust to several alternate specifications.

Conclusions:
Among the strongest and most consistent findings, eliminating punishments for possession for personal use is not associated with higher drug use. The results indicate that researchers should take national-level context into account in individual-level studies of drug use.