In 2012, Colorado became the first state to legalize recreational marijuana use; the first retail stores opened in 2014. A new article examined the effects of recreational marijuana legalization (RML) on college students in Colorado. Data on self-reported marijuana and alcohol use were collected from current college students or recent graduates in four waves (N = 1,413; ns ranged from 256 to 424) over a 17-month period (before and after RML). Snowball sampling was used to recruit new participants. The overall sample was mostly female (77%) and mostly White (76%). Participants completed online surveys on which they reported the frequency, severity, and method of their marijuana and alcohol use. The authors used independent t-tests and ANOVA to analyze changes in frequency of alcohol and marijuana use over time, independent t-tests to compare Colorado data to national data, and logistic regression and Pearson’s correlation to analyze patterns in alcohol and marijuana use in each wave. Participants were sorted into groups, based on their reported frequency of alcohol and marijuana use: No/Infrequent use, use every 2-5 months, use 1-3 times per month, and weekly use. One-way ANOVA was used to explore differences in GPA among these groups. Results indicated a significantly higher proportion of Colorado college students had ever tried marijuana, compared to results from the National College Health Assessment (NCHA) (71% v. 39%, p < 0.001). The average amount of daily or near daily marijuana users was significantly higher in the sample than in NCHA results (25% v. 2%, p < 0.001). No significant differences in frequency of marijuana use were found across waves. Mean GPA for the no/infrequent use group was 0.429 points higher than the weekly use group (p < 0.05). The authors also investigated the relationship between alcohol use and marijuana use at each wave. Moderate positive correlations between frequency of alcohol and marijuana use were observed at all waves, but the strength of these correlations diminished over time. In waves I and II, all three alcohol use groups were significantly different from weekly drinkers, with respect to marijuana use; however, in waves III and IV, only two use groups were significantly different from weekly drinkers. Overall, binge drinking increased the likelihood of using marijuana since RML (ORs at each wave ranged from 2.012 to 6.128, compared to students who did not report binge drinking).
Take away: Following recreational marijuana legalization in Colorado, frequency of marijuana use among college students was significantly higher than the national average, especially for daily or near daily users. There were moderate positive correlations between frequency of marijuana use and frequency of alcohol use; binge drinking increased the likelihood of using marijuana.
Citation: Jones J, Jones KN & Peil J (2017 The impact of the legalization of recreational marijuana on college students [published online ahead of print August 31 2017], Addictive Behaviors doi: 10.1016/j.addbeh.2017.08.015