Researchers see little change in consumption among middle-, high-school students
Oregon State University researchers found that Oregon college students, including those under 21, were much more likely to use marijuana after recreational use became legal, according to a study published this week.
Most of the increase in the post-legalization period was among students who reported using marijuana one to five times a month, not among heavy users, the study found.
The findings among Oregon college students contrast with results on health surveys of Oregon middle- and high-school students. In large, anonymous surveys given to eighth graders and high-school juniors every other year, they did not report much change in marijuana use in 2017 compared to during earlier years before recreational marijuana became legal and the retail pot shops ubiquitous.
For the college study, researchers David Kerr, Harold Bae and Andrew Koval analyzed data from the National College Health Assessment survey, an anonymous voluntary survey that universities across the country distribute to a random sample of their students. Focusing on undergraduate students ages 18 to 26 at two large public universities in Oregon, researchers compared reported usage before and after legalization.
The two universities were not identified. Oregon students’ drug usage after marijuana legalization was derived from fewer than 2,000 student self-reports.
Although marijuana use by college students across the country rose slowly over the past decade, it increased more sharply in Oregon in spring 2016, months after legal retail marijuana shops opened around the state, said Kerr, an associate professor of psychology at Oregon State. This included an increase among underage students, even though recreational marijuana is only legal for users age 21 and older.
In 2016, 17 percent of college students surveyed in states where recreational marijuana was not legal reported they had used marijuana in the last 30 days, compared to 31 percent in Oregon.
“Some would say that’s a concern because marijuana use, particularly in young people, is linked to negative health and achievement outcomes,” Kerr said in a press release announcing the results. “On the other hand, alcohol and tobacco take a huge toll on public health and it is possible that marijuana legalization will affect how many people use other substances.”
The study found that tobacco use by college students in Oregon dropped dramatically in spring 2016 as marijuana use rose. Students’ use of alcohol and other drugs didn’t significantly change.
Researchers noted that survey participation was low, with just 16 percent to 36 percent of students responding during the eight years of surveys used for the study. They also noted that even before legalization, a higher percentage of Oregon college students used marijuana than in states where it wasn’t legal — 26 percent versus 16 percent in 2010. They also found that usage had been on the rise both in Oregon and other states even before it was legalized in Oregon and a handful of other states.
Bae, an assistant professor of biostatistics, said he and his fellow researchers recently received grant funding to study longer-term effects of marijuana use.