Cannabis consumption rates have steadily increased in the United States due to a number of different variables related to accessibility, legality, and decriminalization. Among all age-based population groups, the young adult demographic retains the highest usage rate of cannabis, with college students included in this classification. 17 states have now legalized the recreational sale, possession, and use of cannabis creating a significant demand in research concerning the effects of these new laws. This study aims to delineate the changes of attitudes, intentions, and use of cannabis in groups of college students using a longitudinal approach related to the timing of legalization.
The study consists of two samples of college students, one cohort from a university in Washington state (N=139) and the other from a university in Wisconsin (N=199), which were studied in a longitudinal fashion from pre-freshman year to post-graduation over the course of 5 years from 2011 to 2016. During this time period, the state of Washington legalized the sale of recreational cannabis (Dec. 2012), while Wisconsin did not see significant changes to its laws, thus serving as a control group. Students of each cohort completed 6 phone interviews over the course of this 5-year timespan in which researchers asked a series of questions related to students’ attitudes, intentions, and behaviors related to cannabis consumption. The interview methods were based around a conceptual framework called the Theory of Planned behavior. Attitudes and intentions were measured using Likert scales, while cannabis use was measured using self-reported history. The data was analyzed using Prais–Winsten regressions and general pairwise comparison tests.
Results of the study found similar attitudes, intentions (exception: Wisconsin has significantly higher intention scores during the first year only), and proportions of users across all time points when comparing the two schools. The primary significant difference found over the course of the study was a significant increase in past 28-day usage of cannabis in users in the state of Washington following legalization in 2013 (p<0.05). The total proportion of users did not change and was not significantly different than that of the Wisconsin cohort, indicating behavior changes only in known users rather than an increase in total users.
Takeaway: cannabis use in college students is a complex phenomenon influenced by a variety of factors. When comparing a sample of students who were enrolled during cannabis legalization to a sample who saw no legislative changes during their tenure, the only difference this study detected was an increase in cannabis use in students who were already using cannabis before recreational legalization. Additional research will be needed to determine the effects of ongoing cannabis legalization efforts in the United States.