The use of marijuana among college students in 2018 was at the highest level seen in the past three and a half decades, according to a study from the University of Michigan.
UM's annual Monitoring the Future Panel study also says vaping of marijuana and nicotine doubled for college students between 2017 and 2018.
According to the study, 43 percent of full-time college students aged 19-22 reported using marijuana at least once in the past 12 months. The five-year trend, from 2013 to 2018, increased by 7 percentage points. Twenty-five percent reported using at least once in the prior 30 days. The study says both levels are at historic highs since 1983, when they were 45 percent and 26 percent, respectively.
Thirty-day prevalence of vaping marijuana also increased for college students from 5.2 percent in 2017 to 10.9 percent in 2018, a 5.7 percentage point increase.
"This doubling in vaping marijuana among college students is one of the greatest one-year proportional increases we have seen among the multitude of substances we measure since the study began over 40 years ago," said John Schulenberg, principal investigator of the Monitoring the Future Panel Study, in a news release.
Daily or near daily use of marijuana was at 5.8 percent in 2018 for college students.
"Daily marijuana use, especially among noncollege youth, is worrisome," said Schulenberg. "The brain is still growing in the early 20s, and as the Surgeon General just reported, the scientific evidence indicates that heavy marijuana use can be detrimental to cognitive functioning and mental health.
There likely are multiple reasons for the continuing increase in marijuana use among college students and noncollege youth, according to the researchers. One possible reason is the ongoing decline in perceptions of risk of harm from regular marijuana use.
"Perceptions of great risk peaked at 75% 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, in a news release. "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."
Vaping nicotine also showed dramatic increases for college students, with prevalence rising 9.4 percentage points from 6.1 percent in 2017 to 15.5 percent in 2018.
"2018 showed a rare occurrence, with nicotine use—in this case by vaping it—being higher among college than noncollege youth," Schulenberg said. "Typically, noncollege youth have much higher levels of nicotine use. For example, 30-day cigarette smoking in 2018 was 6.8% among college students and 17% among noncollege youth."
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