(Photo by Esteban Lopez on Unsplash)

NEW YORK — The number of both daily and non-daily cannabis users in the United States across all adult age groups has risen steadily since 2007, according to a study led by researchers at Columbia University’s Mailman School of Public Health.

While everyday cannabis use among younger Americans between ages 12 and 17 decreased before 2007, cannabis use overall among adults increased significantly after that year. That’s because both medical and recreational marijuana laws began being relaxed across the country more frequently. Between 2007 and 2014, the number of states that passed medical marijuana laws doubled from 12 to 24.

Marijuana / cannabis plant
The number of both daily and non-daily cannabis users in the United States across all adult age groups has risen steadily since 2007, a recent study finds. (Photo by Esteban Lopez on Unsplash)

The study also showed that non-daily cannabis use decreased before 2007 for the 12-17 age group as well as the 35-49 segment. Yet after 2007, consumption rose among all adults, especially those aged 26 to 34 (4.5 percent spike). Meanwhile, daily use among adults was the highest in those aged 18 to 34, but increases did not differ significantly across adult ages 18–64 and ranged between 1 and 2 percentage points.

“Increases in daily and nondaily cannabis use among adults after 2007 could be due to increasingly permissive cannabis legislation, attitudes, and lower risk perception,” says first author Dr. Pia M. Mauro, assistant professor of Epidemiology at Columbia, in a statement.

Dr. Mauro and her team used data from the National Survey on Drug Use and Health, which studied individuals aged 12 or older. They examined trends in cannabis use in all age demographics between 2002 and 2014. For the study, they defined daily cannabis use as 300 days over the past year.

“We saw a steady increase in more frequent use among people who reported cannabis use, including young people,” says Mauro. “We found significant increases in daily cannabis use across adult age categories after 2007 that contrasted with stable prevalence before 2007 and decreases among adolescents.”

Interestingly, baby boomers (ages 50-64) were the only group to show non-daily use increase both before and after 2007. The authors say that number could eventually lead that segment to soar past the 35-49 demographic, should the trend continue.

“Research about the patterns and consequences of cannabis use in baby boomers in particular is needed, since use is high in this birth cohort and is expected to continue to increase,” adds Dr. Silvia Martins, an associate professor of epidemiology at the school and senior author of the study. “Moreover, significant increases in nondaily cannabis use among adults 65 and older defy perceptions that older adults do not use cannabis, although daily use in this age group remains rare.”

The full study was published June 13, 2018 in the Journal of Studies on Alcohol and Drugs.

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