Grant: Catalyst Grant: Pop. Health Intervention Research on Legalization of Cannabis

Plans for the legalization and regulation marijuana in Canada focus attention on youth as a sub-group of considerable concerns. This is not unwarranted. Despite its current status as an illegal drug, Canadian adolescents are already among the youngest and most frequent users of marijuana in the developed world. According to a UNICEF survey (2013), 28% of 11 to 15 year old Canadians reported using marijuana in the last year. However, youth differ in their patterns of marijuana use - in both frequency of use and amounts used. Their patterns of use (typically called trajectories) can also change from adolescence to young adulthood. Understanding of the effects of different trajectories of marijuana use by Canadian youth requires longitudinal research and an interdisciplinary lifespan approach that can consider multiple predictors and stage-salient outcomes for men and women. A good deal of current research comes from the US and this research is narrowly focused on the effects small amounts of marijuana use on single. Research is needed to increase our understanding of the diversity of potential impacts of marijuana on Canadian youth. We will examine predictors and impacts of five different patterns of marijuana use (Abstainers, Occasional Users, Increasers, Decreasers and Chronic Users) on economic, academic, social, and mental health outcomes. Sex and gender differences in predictors and consequences of different trajectories of marijuana use will also be examined. We will use existing data collected from 662 (males) youth ages 12 to 18 in 2003 who were interviewed bi-annually for a decade (producing 6 waves of detailed data about their development from adolescence to young adulthood). Knowledge gained from this research will also inform stakeholder discussions about and selection of indicators for a Canada-wide longitudinal study that will improve our ability to monitor how youth are impacted by the legalization and regulation of marijuana.