Changes in emerging adults' alcohol and cannabis use from before to during the COVID-19 pandemic: Evidence from a prospective birth cohort.

OBJECTIVE: Prospective research is needed to better-understand changes in substance use from before to during the coronavirus disease (COVID-19) pandemic, among emerging adults (18-25 years), a high-risk group for substance use. METHOD: N = 1,096 (weighted sample N = 1,080; 54% female) participants enrolled in the Québec Longitudinal Study of Child Development, who completed prepandemic (2019; 21 years) and COVID-19 (mid-March to mid-June 2020) surveys. COVID-19-related and preexisting factors were examined as moderators of change in substance use. RESULTS: Full sample analyses revealed decreased binge drinking (p < .001, Bayes factor [BF] = 22, Cohen's f² = 0.02), but no changes in alcohol and cannabis use. Stratified analyses revealed emerging adults who reported < monthly use prepandemic increased their alcohol use (p < .001, BF > 150, f² = 0.05) and binge drinking (p < .001, BF = 27, f² = 0.01), but not their cannabis use. Conversely, emerging adults who reported >monthly use prepandemic decreased their binge drinking (p < .001, BF > 150, f² = .12) and cannabis use (p < .001, BF > 150, f² = .06), but did not change their alcohol use frequency. Several factors moderated change in substance use, including employment loss (p = .005, BF > 39, f² = .03) and loneliness (p = .018, BF > 150, f² = .10) during COVID-19. CONCLUSIONS: Changes in alcohol and cannabis use frequency among emerging adults in the first 3 months of COVID-19 largely differed according to prepandemic substance use, COVID-19-related factors, and preexisting factors. While some youth with preexisting vulnerabilities (e.g., more frequent substance use prepandemic) remained stable or decreased their substance use during COVID-19, emerging adults who experienced employment loss, loneliness, and financial concerns during COVID-19 increased their substance use, highlighting the need for increased supports for vulnerable populations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The 3D-Transition Study: Objectives, Methods, and Implementation of an Innovative Planned Missing-Data Design.

The prevalence of mental health problems represents a significant burden on school and community health resources as early as preschool. Reducing this burden requires a better understanding of the developmental mechanisms linking children's early vulnerabilities with mental health after the transition to formal schooling. The 3D-Transition Study (2017-2021) follows 939 participants from a pregnancy cohort in the province of Québec, Canada, as they transition to kindergarten and first grade to examine these mechanisms. Biannual assessments include completed questionnaires from 2 parents as well as teachers, parent-child observations, anthropometric measurements, and age-sensitive cognitive assessments. Saliva is also collected on 11 days over a 16-month period in a subsample of 384 participants to examine possible changes in child salivary cortisol levels across the school transition and their role in difficulties observed during the transition. A combination of planned missing-data designs is being implemented to reduce participant burden, where incomplete data are collected without introducing bias after the use of multiple imputation. The 3D-Transition Study will contribute to an evidence-based developmental framework of child mental health from pregnancy to school age. In turn, this framework can help inform prevention programs delivered in health-care settings during pregnancy and in child-care centers, preschools, and schools.