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Background Given the high rates of cannabis use among Canadian youth and that adolescence is a critical period for cannabis use trajectories, the purpose of this paper was to examine the effect of the early stages of the COVID-19 pandemic period on youth cannabis use in the context of a natural experiment. We used 3-year linked data from the COMPASS study, including 7653 Canadian (Quebec, Ontario) adolescents from which 1937 completed all 3 survey waves (pre-COVID-19 [2018, 2019] and online [2020] during the early pandemic period [May–July 2020]). Structural equation modeling (SEM) and double difference (DD) models were used to estimate pre-COVID-19 to initial COVID-19 pandemic period change (2019–2020) in cannabis use (monthly, weekly, daily) compared to 2018 to 2019 change to adjust for age-related effects. Models were adjusted for age of entry into the cohort and sociodemographic characteristics. Results In the SEM and DD models, monthly, weekly, and daily cannabis use increased across all waves; however, the expected increases from the pre-COVID-19 wave (2019) to the initial COVID-19 period wave (2020) were lesser relative to the changes seen across the 2018 to 2019 waves. The cross-sectional data from May to July 2020 identified that the majority of youth who use cannabis did not report increased cannabis use due to COVID-19 or using cannabis to cope with COVID-19. Conclusion During the early stages of the COVID-19 pandemic period, there does not appear to be a detrimental effect on youth cannabis use, when adjusted for age-related changes. Further prospective research is needed to explore the impact of the ongoing pandemic response on youth cannabis use onset and progression.

Background Adolescence is a critical period for vaping onset. The purpose of this paper was to examine the effect of the early stages of the COVID-19 pandemic period on youth vaping. Methods We used 3-year linked data from the COMPASS study, including 7585 Canadian (Quebec, Ontario) adolescents from which 1,949 completed all 3 survey waves (pre-COVID-19 [2018, 2019] and online [2020] during the early pandemic period [May-July 2020]) and provided vaping data. Structural equation modeling (SEM) and difference-in-difference (DD) models were used to estimate pre-COVID-19 to initial COVID-19 pandemic period change (2019-2020) in vaping (monthly, weekly, daily) compared to 2018 to 2019 change to adjust for age-related effects. Models were adjusted for age of entry into the cohort and sociodemographic characteristics. Results In the SEM and DD models, the proportion of youth who were monthly and weekly vaping increased from 2018 to 2019 but decreased from 2019 to 2020; daily vaping increased across all waves. However, for all vaping outcomes modelled, the expected increases from the pre-COVID-19 wave (2019) to the initial COVID-19 period wave (2020) were lesser relative to the changes seen across the 2018 to 2019 waves. Conclusion The early stages of the COVID-19 pandemic period appears to be associated with a reduction in the proportion of youth who were monthly and weekly vapers in our adjusted longitudinal models. While daily vaping increased over this same period of time, the magnitude of the increase in our adjusted longitudinal models appears attenuated by the early stages of the pandemic. Implications This large prospective study of youth that included pre-pandemic data is unique in that we were able to identify that the early stages of the COVID-19 pandemic period was associated with a reduction in the proportion of youth who were monthly and weekly vapers in our adjusted longitudinal models. Conversely, the proportion of youth who were daily vaping increased over this same period of time, but the magnitude of the increase appears smaller than expected during the early stages of the pandemic in our adjusted longitudinal models. This study provides novel robust evidence that the patterns of vaping most aligned with onset and progression (i.e., monthly and weekly use), appear attenuated during the initial pandemic period.

In many countries, only a minority of children grow up healthy. 1 The 2018 World Nutrition Report indicates that stunting affects 150.8 million children under five years of age, which represents 22.2% of the world's children. 2,3 The vast majority of stunted children come from developing countries (148.0 of 150.8 million). 3 These countries also have more out-of-school children or people with low academic achievement than the global average. The United Nations Educational, Scientific and Cultural Organization (UNESCO) Institute for Statistics reports that, in 2018, 17.7% of children of primary school age were out of school in the least developed countries, compared with only 8.2% globally. 4 In the same year, only 54.0% reached the last grade of primary education in developing countries compared with 81.7% globally. 4

Background Adolescents are increasingly aware of the treats of climate change and encouraged to take part in environmental actions. However, the current understanding climate anxiety adolescents is sparse. This study establishes the characteristics of adolescents who experience functional impairments induced by climate anxiety and who adopt pro-environment behaviours. It also characterizes the association between climate anxiety, feelings of self-efficacy and environmental actions. Methods 2 379) from 113 schools in Quebec answered questions about climate anxiety, self-efficacy, behavioural engagement and several indicators of wellbeing. Data were analysed using poisson regressions adjusted for potential confounders (age, gender, school type, material deprivation, etc). Results More than one in ten adolescents (11%) reported that thinking about climate change makes it difficult to sleep or interferes with their ability to get work or assignments done. Only 35% of adolescents believed that they can do something to address the problem and 44% tried to reduce their behaviors that contribute to climate change. Adolescents who are boys and who are less anxious were less preoccupied and involved in the fight against climate change. Teenagers from less affluent families were more concerned, but not more engaged. Those with a good relationship with their family and strong school connectedness were both less concerned and more involved in the fight against climate change. Adolescents who felt they can do something about climate change were more likely to try to reduce behaviors that contribute to climate change. Conclusion The findings are useful to identify and support vulnerable groups that are more likely to experience functional impairments due to climate anxiety. The feeling of climate self-efficacy was not well developed among some groups of adolescents. Improving the youth’s beliefs in their capacity to help address the climate change may be a key strategy to promote pro-environmental actions. As the threat of climate change increases, it will be important to follow the evolution of climate anxiety and engagement amongst adolescents.