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Rising Cannabis Use in the U.S. Unrelated to Legalization

A new study has found that legalization is not a contributing factor to increased cannabis use among American adults.

Cannabis use is rising sharply among adults in the United States, but according to a new study that trend is unrelated to more states legalizing recreational and medical marijuana.

In a study published online in Addiction, researcher William Kerr and others from the Public Health Institute Alcohol Research Group analyzed the marijuana use-related data from National Alcohol Surveys and compared them to changes in state laws.

According to the report, cannabis consumption among men has jumped 14.7 percent since the turn of the millennium. Between 1984 and 2015, consumption among women doubled from 5.5 percent to 10.6 percent. Since 2014, 12.9 percent of all adults report they regularly consume cannabis, up from 6.7 percent ten years earlier.

Since 2012, eight states and Washington D.C. have legalized recreational marijuana. Today, 29 states plus Washington D.C. have legalized marijuana for medical purposes. While the loosening of cannabis laws has provided more opportunities for adults to legally access cannabis, according to the new study, that is not the reason for the increase in consumption.

“Medical and recreational marijuana policies did not have any significant association with increased marijuana use,” the study found. “Marijuana policy liberalization over the past 20 years has certainly been associated with increased marijuana use; however, policy changes appear to have occurred in response to changing attitudes within states and to have effects on attitudes and behaviors more generally in the U.S.”

National polls reinforce the study’s observation of a societal tide change in how the nation views cannabis. A recent study by Quinnipiac University found support for recreational legalization among Americans to now be at 60 percent, while 94 percent support the use of marijuana for medical purposes. The level of support for legalization was the poll’s highest ever recorded.

“Our findings suggest that U.S. society has become more tolerant and accepting of marijuana use and less concerned with risks, which has led to broader use,” Kerr said in a statement. “While it is still too early to judge the impacts of recreational marijuana legalization, it appears that the passage of these policies reflects changing attitudes toward marijuana use, rather than the other way around.”

The study found that an extreme jump in cannabis consumption among adults aged 50-59. Since 2005, men in that age group have seen a 2,220 percent increase, from 0.5 percent to 11.6 percent. Women have seen a 7,200 percent increase, from 0.1 percent to 7.3 percent.

“We found that rates of use among older groups increased quite significantly since the 1980s, especially for men in their fifties and sixties,” said Kerr. “These increases are the results of both cohort and period effects. People born before 1945 had very low lifetime rates of marijuana use. With baby-boomers aging and participating in the general increasing trend, rates of use have risen steeply.”

The full study – “Trends and age, period and cohort effects for marijuana use prevalence in the 1984 to 2015 US National Alcohol Surveys” – is available to access through Wiley Online Library.

Learn more about cannabis and cannabis laws in the U.S. through our research and education page.