ANN ARBOR—College students’ use of marijuana was at the highest levels seen in the past three decades in 2016, and that trend remained true in 2017, according to the annual national Monitoring the Future Panel study.
Heavy marijuana use among youth not in college is also on the rise, according to the most recent findings from the University of Michigan study. Today’s high levels of marijuana use among the nation’s 19-to-22-year-olds result from a gradual increase over the past decade.
In 2017, 38 percent of full-time college students aged 19-22 reported using marijuana at least once in the prior 12 months, and 21 percent reported using at least once in the prior 30 days. Both of these prevalence levels peaked in 2016, the highest found since 1987, and did not change significantly in 2017. The 2017 prevalence levels represent gradual increases since 2006 when they were 30 percent and 17 percent, respectively.
Same-age high school graduates who are not full-time college students show a similar trend over time, though their use of marijuana tends to be higher; in 2017, their annual prevalence was 41 percent and 30-day prevalence was 28 percent, remaining at highest levels since the 1980s.
Daily or near daily use of marijuana—defined as having used on 20 or more occasions in the prior 30 days—was at 4.4 percent in 2017 for college students. This has remained steady for the past three years, down from a recent peak of 5.9 percent in 2014.
In a rather dramatic contrast, daily marijuana use has continued to rise for same-age noncollege youth, reaching its highest level in 2017 at 13.2 percent, doubling over the past decade (from 6.7 percent in 2006). This gap between college and noncollege youth has widened in the past three years, with daily marijuana use now being three times as high among noncollege youth as among college students.
“The continued increase of daily marijuana use among noncollege youth is especially worrisome,” said John Schulenberg, principal investigator of the Monitoring the Future Panel Study. “The brain is still growing in the early 20s, and the scientific evidence indicates that heavy marijuana use can be detrimental to cognitive functioning and mental health.
“Getting a foothold on the roles and responsibilities of adulthood may be all the more difficult for these one-in-eight noncollege youth who use marijuana on a daily or near daily basis. As for college students, we know from our research and that of others that heavy marijuana use is associated with poor academic performance and dropping out of college.”
There are multiple reasons for the continuing increase in marijuana use among college students and noncollege youth. One likely reason is the ongoing decline in perceptions of risk of harm from regular marijuana use. In 2017, 27 percent of those aged 19-22 perceived regular use of marijuana as carrying great risk of harm, the lowest level since 1980.
“This percentage peaked at 75 percent in 1991, when marijuana use among college and noncollege youth was at historic lows,” said Lloyd Johnston, the original principal investigator of the Monitoring the Future study. “We have consistently seen this inverse relationship between perceptions of risks of harm and actual use, with changes in perceptions of risk typically preceding changes in use.”
In 2017, 12-month and 30-day marijuana use were similar for males and females among both college and noncollege youth. But daily use was higher for males than females in both groups.
Thirty-day prevalence of vaping marijuana, based on new questions added to the surveys in 2017, was slightly higher for noncollege youth (7.8 percent) than college students (5.2 percent). Vaping marijuana tended to be more common among males than females in both groups.
These findings come from the annual national Monitoring the Future Panel Study, which has been tracking substance use among American college students and noncollege youth since 1980. It is conducted by a team of U-M research professors and funded by the National Institute on Drug Abuse. Results are based on data from college students one to four years beyond high school graduation enrolled full-time in a two- or four-year college in March of the given year, compared with same-age high school graduates not enrolled full-time in college.
This ongoing annual study also examined the use of other illicit drugs, alcohol and tobacco. In 2017, use of most substances remained steady or decreased somewhat.
Study results include: