Cannabis Used 20% More Frequently In States That Legalized Recreational Use, Study Finds


People living in states where recreational cannabis is legal use marijuana 20% more often than people in states where it’s illegal, according to a study published Thursday in the journal Addiction, amid a nationwide increase in cannabis use.

Key Facts

People in Colorado said they have used cannabis 24% more frequently than people in Minnesota, according to the study conducted by researchers from the University of Minnesota, who relied on survey data from the Colorado Boulder Center for Antisocial Drug Dependence of nearly 3,500 participants taken between 2018 and 2021, after Colorado became the first state to legalize recreational cannabis in 2014.

The study also highlighted data from the Minnesota Center for Twin Family Research, which studied more than 100 sets of identical twins living in the two states and which researchers say helps control for factors such as family setting and shared genes.

The study found the siblings living in Colorado used cannabis 20% more than those living in Minnesota, where only medical marijuana is legal.

Researchers also found people who had used cannabis before it was legalized were more likely to increase their use after legalization, while people who had not previously used it weren’t more likely to use it afterwards.

The results build on findings from a study published Monday by the National Institutes of Health that found 43% of U.S. adults ages 19 to 30 used cannabis in the past year, a nine-point rise from the 34% of young adults who reported using it five years ago — the study also found a surge in the use of hallucinogens, including LSD, peyote and psychedelic mushrooms.


Although proponents of recreational dispensaries argue cannabis doesn’t pose a significant health risk, several recent studies have pointed out that people who use cannabis are at much greater odds of being hospitalized or visiting the emergency room. One study published in June in BMJ Open Respiratory Research found cannabis users were 22% more likely to go to the emergency room for a variety of reasons, including acute trauma, respiratory problems and gastrointestinal issues — although the study did not definitively say the increase in ER visits was the direct result of cannabis use. Research published on Wednesday in the New England Journal of Medicine also found “unintentional cannabis poisonings” skyrocketed among children under 10 in Canada, where there’s been a six-fold increase in hospitalizations since the country legalized the sale of cannabis for recreational use in 2018. The spike was even higher in Alberta, British Columbia, and Ontario, where the sale of cannabis gummies, chocolates and baked goods is permitted, according to the study. Sweets made with cannabis have been argued to be more appealing to children.

Key Background

Even though cannabis is banned at the federal level, 19 states and Washington, D.C. have legalized the sale of recreational cannabis, making it legal for 141 million Americans who live in those states. Other states, such as Oklahoma, are considering measures to legalize it. A total of 37 states have legalized the sale of cannabis for medical use, and while evidence suggests the non-psychoactive compound CBD could be useful to treat chronic pain, sleep loss, eating disorders and Parkinson’s disease, there’s still a lot unknown about the benefits of CBD or the psychoactive compound THC. A Gallup poll released last November found Americans’ support for legalization rose 10 points since 2013, to 68% in 2021, including 83% of Democrats and 50% of Republicans. Some 60% of U.S. adults in a Pew Research survey released in April 2021 said they believe medical and recreational use should be legalized, while 31% only want medical use to be legal and 8% don’t want to see either legalized. A bill to lift the federal prohibition passed in the House of Representatives in April, marking the second time the House approved the bill — but efforts have stalled in the Senate. Last month, however, Senate Democrats proposed a separate piece of legislation to lift the prohibition — but it’s expected to fail.

Big Number

$25 billion. That’s how much money U.S. dispensaries brought in from cannabis sales in 2021 — and economists believe sales are growing. A study by MJBiz predicts legal sales will top $33 billion by the end of the year.

Further Reading

A Record High: More Young Adults Used Marijuana And Hallucinogens Last Year Than Ever Before, NIH Study Finds (Forbes)

Cannabis Tourism Is Now A $17 Billion Industry—And It’s Just Taking Off (Forbes)

Recreational Cannabis Not As Harmless As People Think, Study Suggests (Forbes)