Predictors of Change in Cannabis Use Status from Pre- to Post-Recreational Cannabis Legalization in Canada: Evidence from a Two-Wave Longitudinal National Survey.

OBJECTIVE

In October 2018, the Government of Canada legalized cannabis for recreational use nationwide. The effects of legalization on cannabis use have been primarily assessed through cross-sectional surveys.

METHOD

In the present study, a two-wave longitudinal design was used to explore potential demographic, substance use and behavioral addiction, and mental health predictors of change in cannabis use status following legalization. Canadian online panelists (18+) were initially surveyed about their gambling and substance use in 2018 (i.e., before cannabis legalization). From the original sample, 4,707 (46.2%) were retained in the follow-up survey one year later, post-cannabis legalization. These respondents were the focus of the present study.

RESULTS

When queried about how legalization would impact their use, 61.8% said, 'I'll never use it', 21.1% stated "I'll use it about the same as I do now," 10.3% indicated, "I may try it for the first time," 5.0% answered, "I'll use it more," and 1.9% responded that, "I'll use it less." Consistent with these sentiments, within the retained sample there was a modest but significant increase in cannabis use from baseline (18.4%) to follow-up (26.1%). Regressions established that younger age, being male, substance use, tobacco or e-cigarette use, problematic gambling, and stated intention to use cannabis were predictors of later cannabis use.

CONCLUSIONS

This national cohort design indicates that cannabis use appears to have increased in Canada following legalization. The present study makes a unique contribution by also identifying variables that statistically forecast movement toward and away from cannabis use.