Abstract
PURPOSE: As legal recreational marijuana use expands rapidly across the U.S., there is growing concern that this will lead to higher rates of use among college-aged young adults. Given the limited research addressing this issue, a longitudinal study was conducted to evaluate the effects of legalizing recreational use on the attitudes, intentions, and marijuana use behaviors of college students in two different legalization contexts, Washington State and Wisconsin. METHODS: Survey data assessing marijuana attitudes, intentions, and use behavior were collected from 2011 to 2016 on a longitudinal cohort of 338 students at two large public universities in Washington and Wisconsin. Time series analyses were conducted to evaluate postlegalization changes in ever use, 28-day use, and mean attitude and intention-to-use scores in Washington state, using Wisconsin participants as the control group. RESULTS: Ever use, attitude, and intention-to-use scores did not change significantly more in Washington after legalization than in Wisconsin. However, among prior users, the proportion using in the last 28 days rose faster in Washington after legalization that it did in Wisconsin (p < .001). CONCLUSIONS: The findings suggest that legalization had the greatest effects on current marijuana users, who are surrounded by a climate that is increasingly supportive of its use.