Adolescent substance use: beware of international comparisons

To compare prevalence estimates of adolescents' cigarette, alcohol and marijuana use from one Australian and two U.S. surveys, and to consider the effect of methodological differences on reported use.

Secondary analysis of data from the Australian Child and Adolescent Component of the National Survey of Mental Health and Well-being (NSMHWB, 1998), the U.S. Youth Risk Behavior Survey (YRBS, 1999), and National Household Survey on Drug Abuse (NHSDA, 1998). Prevalence estimates and 95% confidence intervals were derived for three substance use behaviors. Differences between estimates were considered statistically significant if the 95% confidence intervals did not overlap.

When Australian and U.S. adolescents were compared using NSMHWB and YRBS data, the former were generally found to be less likely to report using cigarettes, alcohol and marijuana than the latter. However, when NHSDA was used as the comparator, the prevalence of substance use among Australian adolescents was either no different from, or greater than, that of U.S. adolescents. Likely explanations for the discrepant findings include the population focus (i.e., whether the survey targeted only young people or adults as well), sampling issues (i.e., whether school-based and household-based sampling frames introduced different biases in terms of who was likely to be absent when the survey was administered), response rates, the survey context (i.e., whether school-based and household-based survey administration methods promoted different kinds of response behavior), the wording of questions and the precision of estimates of the different surveys.

Cross-national data on adolescent substance use should be interpreted cautiously. Cross-national comparisons that are done well (i.e., using standard, uniform approaches) can be invaluable in highlighting worthwhile policy directions; cross-national comparisons that are done poorly may lead to erroneous assumptions.