Adolescent alcohol drinking and cannabis use: Longitudinal, and cohort analysis of high school students in Australia

Abstract

Aims: The final year of high school is a challenging phase, during which substance use is common. We conducted longitudinal and cohort comparisons on the levels of alcohol and cannabis use among final year (Year 12) high school students compared to the previous year. Design: Longitudinal and cohort analyses of self-reported survey data. Setting: Ten independent schools across South-East Queensland, Australia. Participants: Year 12 students in 2020 (n = 1024) were compared (a) longitudinally with themselves in Year 11; and (b) to the 2019 Year 12 cohort (n = 632). Measures: Self-reported alcohol and cannabis use. Analyses adjusted for socio-demographic, parental, and schooling variables. Findings: Longitudinally, Year 12 students of 2020 had higher odds of having six or more drinks per occasion, monthly or more often, and reporting lifetime cannabis use, compared to themselves in 2019. However, they were not more likely to drink alcohol weekly or more often in 2020 versus 2019. Compared to the 2019 cohort, the 2020 cohort had higher odds of drinking weekly or more often, having six or more drinks per occasion monthly, and reporting lifetime cannabis use. Conclusions: The 2020 cohort of Year 12 adolescents were more likely to engage in heavy drinking and cannabis use, compared to themselves the previous year, and compared to the previous cohort. Greater alcohol consumption and likelihood of cannabis use among the 2020 cohort might be explained by increased age and impacts of the COVID-19 pandemic. Future research to monitor if this is a continuing trend is warranted.