BACKGROUND Monitoring the prevalence of problematic cannabis use is an important public health issue. International surveys need invariant measurement tools to allow reliable comparisons across countries and between sexes. The Cannabis abuse screening test (CAST) has been developed for this purpose. This study is the first assessing its country and sex invariance in a sample of European pupils.

METHODS The data come from the self-administered questionnaires completed in 2019 by pupils aged 15-16 in the European school survey project (Espad). The analytical sample was restricted to the 17 countries where at least 300 pupils reported a previous-year cannabis use (n = 8740); multigroup confirmatory factor analyses were used to assess the configural, metric and scalar invariance of the CAST toward country and sex in the 2019 Espad release.

RESULTS Configural, metric and scalar invariance toward country hold for the 17 countries: Austria, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Greece, Italia, Latvia, Poland, Portugal, Slovakia, Slovenia and Spain. Scalar invariance toward sex was met in the 17 countries as a whole and in 11 of the 12 countries where the test could be run. Scalar invariance toward country was met with 6 additional countries comprising at least 250 respondents: Ireland, Lithuania, Malta, Montenegro, the Netherlands and Norway.

CONCLUSION The CAST is a suitable test for comparing the measurement of problematic cannabis use amongst adolescents in Europe.