Grant: Op. Gr.:Cannabis Res. in Longit. studies-Neurosciences, Ment. health/Addiction

Since non-medical cannabis use was legalized in Canada in 2018, prime working-age adults report the largest increase in the prevalence of cannabis use compared to other age groups. Also, limited evidence suggests that using cannabis to cope with symptoms of anxiety and depression is widespread in this age group as they undergo multiple life transitions. The CANnabis research DevelOpment (CAN-DO) research program seeks to generate new knowledge on cannabis use/co-use in a well-established population-based cohort of prime working-age adults. Our objectives are: (i) to describe reasons for cannabis use and types of cannabis used; (ii) to describe the natural course of cannabis use and identify the sociodemographic and genetic underpinnings of the natural course; and (iii) to investigate the acute and long-term associations between cannabis use and mental health (i.e., stress, worry, positive mental health, depressive and anxiety symptoms, dependence on cannabis). Our proposal capitalizes on the Nicotine Dependence in Teens (NDIT) study, a 22-year investigation of 1294 adolescents recruited in 10 Montreal-area high schools in 1999-2000, with 24 data collections to date spanning ages 12 to 33, and 2 upcoming (already funded) data collection cycles in 2022 and 2023. Data collection in the upcoming cycles will document reasons for using cannabis, frequency and intensity of use, access, CBD/THC content, mode of administration, co-use with other substances, anxiety and depressive symptoms, and other measures of mental health. In this current request to CIHR, we also propose 2 new sub-projects among cannabis users. The first is a qualitative study to investigate motivations for and perceived effectiveness of cannabis use in managing symptoms of depression, anxiety and stress or worry. The second project is an Ecological Momentary Assessment study that will document motivations for and acute responses to cannabis use.