Parental education, child’s grade repetition and the modifier effect of cannabis use

Abstract

Previous research on the relationship among family socio-economic status (SES), cannabis use and educational attainment has concentrated on finding a causal pathway from SES and illicit drug use to educational achievement. However, the association between family background and a child’s cannabis use is weak. When analysing both family SES and education as determinants of a child’s educational attainment, cannabis use should be treated as an effect modifier rather than a confounder. This article examines how cannabis use alters the protective effect of better family education on a child’s school performance. By means of a retrospective cohort study using data from the Spanish National Survey on Drug Use in Secondary Education, this study illustrates that, as expected, children of better-educated parents are less likely to repeat a grade, although the positive impact of higher family education vanishes when students use cannabis.