Grant: CIHR New Investigator

The use of tobacco, alcohol and marijuana by teenagers continues to pose a significant threat to the health and safety of many young Canadians. Recent national surveys indicate that 15 percent of Canadian teens smoke tobacco; one third of all teens have tried marijuana more than once with about 8 percent of teens reporting marijuana use of at least once a week. Just over 44 percent of teens reported drinking 1 to 3 times per month with an additional 17 percent of teens aged 15 to 17 drinking 1 to 3 times a week or more. Despite extensive prevention efforts, the use of these substances appears to have become a normalized part of adolescence. The goal of this study is to investigate patterns in the progression of substance use, using an internet-based web-survey, in approximately 5,000 adolescents as they progress through the first 3 years of secondary school. We plan to group adolescents into different trajectories of alcohol, tobacco and marijuana use and then examine how the level and influence of known risk factors (e.g., sensation seeking and peer substance use) change as adolescents enter and then progress through high school. The information gained from this study will improve our understanding of the determinants of individual differences in the development of alcohol, tobacco, and marijuana use. The findings will be shared with health promotion experts and school district supervisors to inform local drug education and health promotion activities.