By Robert Preidt
Researchers analyzed federal government data and found that non-daily marijuana use fell among Americans aged 12 to 25 and 35 to 49 before 2007, but rose among all adults after 2007. This was particularly true among adults 26 to 34 -- a 4.5 percent increase.
Daily marijuana use was highest among adults aged 18 to 34. Adults aged 50 to 64 were the only age group with increases in non-daily marijuana use both before and after 2007, the researchers reported.
If the trends continue, marijuana use by adults aged 50 to 64 could surpass that of the 35-to-49 age group, according to the study.
"Increases in daily and non-daily cannabis use among adults after 2007 could be due to increasingly permissive cannabis legislation, attitudes, and lower risk perception," study first author Pia Mauro, an assistant professor of epidemiology at Columbia University's School of Public Health, said in a university news release.
As of September 2017, medical marijuana was legal in 29 states and the District of Columbia, and recreational use was legal in eight states and the District of Columbia, the researchers noted.
Study senior author Dr. Silvia Martins said that "not all adults use cannabis at the same rate. Understanding the ages at which young people and adults use cannabis can help target appropriate reduction or prevention interventions." Martins is an associate professor of epidemiology at the School of Public Health.
"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," Martins said.
She added that "significant increases in non-daily 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 study, published online in the May issue of the Journal of Studies on Alcohol and Drugs, was funded by grants from the U.S. National Institute on Drug Abuse and the New York State Psychiatric Institute.
On Wednesday, Canadian lawmakers approved the recreational use of marijuana, making it just the second country to do so.