British Columbia

Teen use and perceptions of marijuana change after legalization, U.S. study finds

A new study out of the University of California Davis found teen marijuana use in Washington State went up after marijuana was legalized.

Researchers found that marijuana use went up among some — but not all — teens after legalization

This year is expected to be a pivotal one for the marijuana industry in Canada, with the federal government planning on tabling new legislation in the spring. (CBC)

A study out of the University of California, Davis has provided new insights into how marijuana legalization affects teenagers' perceptions and use of the drug.

Researchers found that among Grade 8 and 10 students in Washington State, marijuana use increased after the drug was legalized. 

Attitudes were also affected. The study's findings showed teenagers were less concerned about the harms associated with marijuana after the law changed.

Results varied among slightly older students. Among Grade 12 students, no shift in attitude or use was reported.

In Colorado, where marijuana was legalized in 2012, the study's results were also different. Researchers found no change in attitude or use of marijuana after legalization — for any age group.

Lead researcher Magdalena Cerda said she believes the changes in attitudes and frequency of use are directly linked.

"It could be a combination of things that led to the increase in use among adolescents — but likely any change of use in our study is due to changes in perceptions about the harmfulness of marijuana," she said. 

She said that other factors — including increased access to marijuana and the drop in price following legalization — are also likely to be contributing factors.

Canadian policy in the works

This year is expected to be a pivotal one for the marijuana industry in Canada, with the federal government planning on tabling new legislation in the spring.

Cerda said policy makers should consider scientific findings, especially with respect to young people, while designing laws.

"There's a real concern about the de-stigmatization of marijuana among adolescents," she said. 

"As places like Canada consider legalizing, they should pay attention to the importance of having accurate information associated with early initiation of marijuana use — particularly among adolescents."

Cerda said that while teenagers who begin using marijuana at a young age are more likely to become dependent on the drug, the real concern for any user is long-term, consistent use over many years.

The U.S. states that have legalized marijuana sales have opted to match the legal drinking age of 21. 

The Canadian Medical Association also recommends the age limit be 21, with strict limits on quantity and potency until 25.


With files from CBC Radio's On The Coast