Increase in cannabis use among high school students in Canada after legalization: study

A recent study has shown an increase in high school students’ consumption of the drug immediately preceding federal legalization Oct. 17 last year.

Researchers studied data from a questionnaire completed by 230,000 Canadian teens. About 18 percent of Grade 9 to 12 students reported having consumed cannabis once within the past year, and nearly 10 percent reported having used at least once a week from 2017 to 2018.

This is up from 2014-2015 when 15 percent reported occasional use and 9 percent reported regular use. The report took data from an annual survey completed by Alberta and Ontario high school students known as the COMPASS Study.

Indigenous youth showed a significant increase in use, rising from 23 percent to 25 percent using weekly in the same time period, and 18 percent to 21 percent using occasionally. Female students also reported higher rates of use. The percentage of female students using cannabis on a weekly basis rose from 7 percent to 8 percent, and occasional use rose from 17 percent to 19 percent.

About 18 percent of Grade 9 to 12 students reported having consumed cannabis once within the past year, and nearly 10 percent reported having used at least once a week from 2017 to 2018.

Rates of regular and occasional cannabis consumption were highest among Indigenous students at 55 percent and 46 percent, from 2017 to 2018. The lowest reported rate of use was among Asian teens, at 17 percent and 14 percent, respectively.

Despite female students showing a larger increase in reported use, male users reported higher rates of overall use, with 33 percent reporting weekly use and 29 percent reporting use in the past year. 31 percent of female students reported regular use, and 26 percent reported past-year consumption.

“The problem was developing while legalization was being discussed, but well before concrete steps to change the law were taken,” lead author Alexandra Zuckermann told University of Waterloo news. Zuckermann is a post-doctoral fellow with the Public Health Agency of Canada and works in the School of Public Health and Health Systems.

“With medicinal use more widespread and talk of total legalization starting, we saw a shift in public perception starting around 2014. Before that, youth cannabis use was declining. These changing social norms may have contributed to rising youth use.”

Hospitals in Alberta and Ontario are also reporting a spike in ER visits due to cannabis poisoning around the same time. According to the Canadian Institute for Health Information (CIHI), 582 of those visits were by individuals under 20 years of age during the 2017-18 fiscal year, up from 364 visits in 2016-17 and 298 in 2013-14.

Of the 582, 24 of those ER visits were made by children under 5.

Adults who enjoy cannabis are encouraged to keep cannabis products in a child-proof container within a locked cabinet in order to prevent youth from accessing the drug.