Marijuana Trajectories and Associations with Driving Risk Behaviours in Canadian Youth
Author(s): Sukhawathanakul, Ames, Leadbeater
Slidedeck Presentation Only (no paper submitted):
Abstract:
A better understanding of the longitudinal patterns of marijuana use and its effect on risky driving practices during young adulthood is needed. To determine whether differences in the patterns of marijuana use over the course of adolescence are associated with driving risks in young adulthood. Participants were part of the longitudinal Victoria Healthy Youth Survey. Youth (baseline ages 12 to 18; N = 662; 52% females) were interviewed biannually (on 6 occasions) from 2003 to 2013 and classified as 'Abstainers' (29%;who never used), 'Occasional users' (27%; started as abstainers in adolescence, and increased use up to a 'few times a year' after age 17), 'Decreasers' (14%; used marijuana a few times per month at age 15 and decreased to less than a few times per year by age 23), 'Increasers' (20%; already used a few times per year by age 15 and increased rapidly, peaking at more than once per week about age 22 and then declining to a few times per month by age 28), and 'Chronic users' (11%; used marijuana more than once per week across all ages). Chronic users were mostly likely to report risky driving behaviours compared to the other user groups (Occasional users, Decreasers, or Abstainers) with the exception of the Increasers group. In particular, 42% of Chronic users reported that they have been 'physically at-risk' while high or intoxicated, 71% 'had been in a car or other vehicle when the driver (including themselves) had been using marijuana or other drugs', and 56% 'had been in a car or other vehicle when the driver (including themselves) had been drinking alcohol.' The proportion of Increasers who reported driving risks were not significantly different than the Chronic Users; 34% users reported that they have been 'physically at-risk' while high or intoxicated, 51% 'had been in a car or other vehicle when the driver (including themselves) had been using marijuana or other drugs,' and 35% 'had been in a car or other vehicle when the driver (including themselves) had been drinking alcohol.' The proportions of Increasers who reported driving risks were also higher than the other user groups (i.e., the Occasional users, Decreasers, or Abstainers). Findings demonstrate the existence of two at-risk groups of youth who chronically use marijuana over the course of adolescence and young adulthood, and who are more likely to be at-risk of driving-related harms compared to youth who abstain, occasionally use, or are decreasing in their usage over time. The prevalence of these chronic users engaging in more risky driving practices highlights the need for prevention and education regarding the dangers of using marijuana on the road.