College students use more marijuana in states where it's legal, but they binge drink less
January 13, 2020
Science Daily/Oregon State University
Marijuana use among college students has been trending upward for years, but in states that have legalized recreational marijuana, use has jumped even higher.
An Oregon State University study published today in Addiction shows that in states where marijuana was legalized by 2018, both occasional and frequent use among college students has continued to rise beyond the first year of legalization, suggesting an ongoing trend rather than a brief period of experimentation.
Overall, students in states with legal marijuana were 18% more likely to have used marijuana in the past 30 days than students in states that had not legalized the drug. They were also 17% more likely to have engaged in frequent use, defined as using marijuana on at least 20 of the past 30 days.
The differences between states with and without legalization escalated over time: Six years after legalization in early-adopting states, students were 46% more likely to have used marijuana than their peers in non-legalized states.
Between 2012 and 2018, overall usage rates increased from 14% to 17% in non-legalized states, but shot up from 21% to 34% in the earliest states to legalize the drug. Similar trends appeared in states that legalized marijuana more recently.
Conducted by Harold Bae from OSU's College of Public Health and Human Sciences and David Kerr from OSU's College of Liberal Arts, this is the first study of college students to look broadly at multiple states that have legalized recreational marijuana and to go beyond the first year following legalization.
It includes data from seven states and 135 colleges where marijuana was legalized by 2018 and from 41 states and 454 colleges where recreational use was not legal.
That scope allowed Bae and Kerr to examine trends in the earliest adopting states as well as more recent adopters -- though, the data for the study is stripped of state- and college-identifying information, so does not speak specifically to any one state or institution.
The data comes from the National College Health Assessment survey from 2008 to 2018, which asks about a wide range of health behaviors including drug and alcohol use and is administered anonymously to encourage students to respond more honestly. More than 850,000 students participated.
Looking at specific demographics, researchers found that the effect was stronger among older students ages 21-26 than minors ages 18-20; older students were 23% more likely to report having used marijuana than their peers in non-legalized states. The effect was also stronger among female students and among students living in off-campus housing, possibly because universities adhere to federal drug laws that still classify marijuana as an illegal substance.
"It's easy to look at the findings and think, 'Yeah, of course rates would increase,'" Kerr said. "But we need to quantify the effects these policy changes are having."
Furthermore, he said, researchers are not finding increases in adolescents' marijuana use following legalization. "So it is surprising and important that these young adults are sensitive to this law. And it's not explained by legal age, because minors changed too."
A recent companion study published in Addictive Behaviors in November by OSU doctoral candidate Zoe Alley along with Kerr and Bae examined the relationship between recreational marijuana legalization and college students' use of other substances.
Using the same dataset, they found that after legalization, students ages 21 and older showed a greater drop in binge drinking than their peers in states where marijuana was not legal. Binge drinking was defined as having five or more drinks in a single sitting within the previous two weeks.
Researchers have not yet tested any hypotheses as to why binge drinking fell, but they have some ideas.
An outside study previously found that illegal marijuana use decreases sharply when people hit 21 -- where there is a sharp increase in alcohol use.
"When you're under 21, all substances are equally illegal," Alley said. "In most states, once you reach 21, a barrier that was in the way of using alcohol is gone, while it's intact for marijuana use. But when marijuana is legal, this dynamic is changed."
Binge drinking has been on the decline among college students in recent years, but dropped more in states that legalized marijuana than in states that did not.
"So in these two studies we saw changes after legalization that really differed by substance," Kerr said. "For marijuana we saw state-specific increases that went beyond the nationwide increases, whereas binge drinking was the opposite: a greater decrease in the context of nationwide decreases."
The magnitude of effect was much larger with marijuana than with any of the other substances, Bae added. "So the changes following recreational marijuana legalization were quite specific to cannabis use."
Future research is needed to see how those trends hold up over time, as additional states legalize marijuana and existing states continue to tweak their current policies, the researchers said.
https://www.sciencedaily.com/releases/2020/01/200113131637.htm
Marijuana use among college students on rise following Oregon legalization
June 14, 2017
Science Daily/Oregon State University
College students attending an Oregon university are using more marijuana now that the drug is legal for recreational use, but the increase is largely among students who also report recent heavy use of alcohol, a new study has found.
Oregon State University researchers compared marijuana usage among college students before and after legalization and found that usage increased at several colleges and universities across the nation but it increased more at the Oregon university. None of the universities were identified in the study.
"It does appear that legalization is having an effect on usage, but there is some nuance to the findings that warrant further investigation," said the study's lead author, David Kerr, an associate professor in the School of Psychological Science in OSU's College of Liberal Arts.
"We found that overall, at schools in different parts of the country, there's been an increase in marijuana use among college students, so we can't attribute that increase to legalization alone."
The results were published today in the journal Addiction. Co-authors are Harold Bae and Sandi Phibbs of OSU's College of Public Health and Human Sciences and Adam Kern of the University of Michigan.
The study is believed to be the first to examine marijuana usage patterns following legalization of recreational marijuana in Oregon and the first to examine the effects of any state's legalization on college students. Voters in Oregon approved legalization in 2014 and the law took effect in 2015.
Oregon's legalization of marijuana is part of a larger trend among U.S. states, but little research has been done so far to understand the impact. In their study, Kerr and his colleagues set out to begin addressing some of those questions.
"It's an important current issue and even the most basic effects have not been studied yet, especially in Oregon," he said. "There are a lot of open questions about how legalization might affect new users, existing users and use of other substances."
Researchers used information collected in the Healthy Minds Study, a national survey of college students' mental health and well-being -- including substance use -- conducted by the University of Michigan. The study is designed to give colleges and universities information to help them understand the needs of their student populations.
As part of the survey, participants are asked about marijuana and cigarette use in the previous 30 days, as well as frequency of heavy alcohol use within the previous two weeks.
Using data from a large public university in Oregon and six other four-year universities around the country where recreational marijuana is not legal, researchers compared rates of marijuana use before and after the drug was legalized in Oregon. They also examined frequency of heavy alcohol use and cigarette use at those points.
The researchers found that the overall rates of marijuana use rose across the seven schools. Rates of binge drinking -- where a person consumes four to five or more drinks in a period of about two hours -- stayed the same and cigarette use declined in that period.
"It's likely that the rise in marijuana use across the country is tied in part to liberalization of attitudes about the drug as more states legalize it, for recreational or medical purposes or both," Kerr said. "So legalization both reflects changing attitudes and may influence them even outside of states where the drug is legal."
Researchers also found that marijuana use rates were generally higher, overall, among male students; those living in Greek or off-campus housing; those not identifying as heterosexual; and those attending smaller, private institutions.
One area where legalization had a marked impact was among college students who indicated recent binge drinking; students at the Oregon university who reported binge drinking were 73 percent more likely to also report marijuana use compared to similar peers at schools in states where marijuana remains illegal.
"We think this tells us more about the people who binge drink than about the effects of alcohol itself," Kerr said. "Those who binge drink may be more open to marijuana use if it is easy to access, whereas those who avoid alcohol for cultural or lifestyle reasons might avoid marijuana regardless of its legal status."
The researchers also found that Oregon students under age 21 -- the minimum legal age for purchasing and using marijuana -- showed higher rates of marijuana use than those over 21.
"This was a big surprise to us, because legalization of use is actually having an impact on illegal use," said Bae, the study's primary statistician.
These initial findings about marijuana use among college students help form a picture of how legalization may be affecting people, Kerr said, but more study is needed before researchers can quantify the harms or net benefits of legalization for young people.
"Americans are conducting a big experiment with marijuana," Kerr said. "We need science to tell us what the results of it are."
https://www.sciencedaily.com/releases/2017/06/170614160510.htm