Since states first began considering medical marijuana laws, claims have frequently been made that the laws “send the wrong message” to adolescents, causing their marijuana use to increase. Now, nearly 25 years since the passage of the nation’s first effective state medical marijuana law, a considerable body of data has found that those fears were not warranted.
Thirty-six states and Washington, D.C. now have effective medical marijuana laws.1 In 32 of the states, government surveys have produced before-and-after data on teens’ marijuana use. In 23 states, the data indicates overall decreases, 11 of which were outside confidence intervals. Only a single state’s data indicates an increase outside of the confidence interval. Other researchers and health experts have examined the data in recent years and have also found the data to be reassuring.As an exhaustive 2019 study published in JAMA Pediatrics concluded, “Consistent with the results of previous researchers, there was no evidence that the legalization of medical marijuana encourages marijuana use among youth.”2
Below is a review of the most comprehensive data on teens’ current (past 30 day) marijuana use in each of medical marijuana states. In all states where such data is available, rates are presented for all high schoolers. In states where data is not available, this uses data from the oldest grade with before-and-after data: 11th grade in California, Oregon, and Minnesota, and 12th grade in Washington.
Oregon Public Schools Drug Use Survey and Oregon Healthy Teens
Washington (1998)
28.7% (12th graders, 1998)
26.2% (12th graders, 2018)
decrease (changed survey)
Washington State Survey of Adolescent Health Behaviors and Healthy Youth Survey
Maine (1999)
30.4% (1997)
22.3% (2019)
decrease
The CDC’s YRBSS
Hawaii (2000)
24.7% (1999)
17.2% (2019)
decrease
The CDC’s YRBSS
Nevada (2000)
25.9% (1999)
19.8% (2019)
decrease
The CDC’s YRBSS
Colorado (2000)
The only before-and-after data available for Colorado is from the National Survey on Drug Use & Health (NSDUH). However, the NSDUH advises that data from 2002 and later is not comparable to prior years’ data due to methodological changes.3
Vermont (2004)
28.2% (2003)
26.5% (2019)
decrease
The CDC’s YRBSS
Montana (2004)
23.1% (2003)
21.1% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
Rhode Island (2006)
25% (2005)
23.0% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
New Mexico (2007)
26.2% (2005)
27.7% (2019)
increase (within confidence interval)
The CDC’s YRBSS
Michigan (2008)
18.0% (2007)
21.6% (2017)
increase
The CDC’s YRBSS
New Jersey (2010)
20.3% (2009)
20.1% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
Arizona (2010)
23.7% (2009)
26.1% (2019)
increase (within confidence interval)
The CDC’s YRBSS
Delaware (2011)
25.8% (2009)
26.1% (2017)
increase (within confidence interval)
The CDC’s YRBSS
Connecticut (2012)
24.1% (2011)
21.7% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
Massachusetts (2012)
27.9% (2011)
26.0% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
New Hampshire (2013)
28.4% (2011)
26.1% (2019)
decrease
The CDC’s YRBSS
Illinois (2013)
23.1% (2011)
21.8% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
Maryland (2014)
19.8% (2013)
17.6% (2019)
decrease
The CDC’s YRBSS
Minnesota (2014)
16.6% (11th graders, 2013)
15.5% (11th graders, 2019)
decrease
Minnesota Student Survey
New York (2014)
21.4% (2013)
19.1% (2019)
decrease
The CDC’s YRBSS
Louisiana (2016)
17.5% (2013)
19.0% (2019)
increase (within confidence interval)
The CDC’s YRBSS
Pennsylvania (2016)
18.2% (2015)
19.6% (2019)
increase (within confidence interval)
The CDC’s YRBSS
Ohio (2016)
20.7% (2013)
15.8% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
Arkansas (2016)
17.8% (2015)
17.5% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
Florida (2016)
21.5% (2015)
19.6% (2019)
decrease
The CDC’s YRBSS
North Dakota (2016)
15.2% (2015)
12.5% (2019)
decrease
The CDC’s YRBSS
West Virginia (2017)
16.5% (2015)
18.9% (2019)
increase (within confidence interval)
The CDC’s YRBSS
Oklahoma (2018)
15.9% (2017)
17.0% (2019)
increase (within confidence interval)
The CDC’s YRBSS
Missouri (2018)
19.9% (2017)
16.3% (2019)
decrease (within confidence interval)
The CDC’s YRBSS
Utah (2018)
8.1% (2017)
10.0% (2019)
increase (within confidence interval)
The CDC’s YRBSS
Virginia (2020)
No “after” data available, law is too new.
Mississippi (2020)
No “after” data available, law is too new.
South Dakota (2020)
No “after” data available, law is too new.
This data should put to rest claims that removing criminal penalties from seriously ill patients’ medical use of marijuana increases teens’ marijuana use.
1 Thirteen additional states have some other type of law that acknowledges the medical benefits of at least certain strains and preparations of cannabis. Only a few of them have workable systems for in-state access. 2 Anderson DM, Hansen B, Rees DI, Sabia JJ. "Association of Marijuana Laws With Teen Marijuana Use: New Estimates From the Youth Risk Behavior Surveys," JAMA Pediatr. 2019;173(9):879–881. 3 Were one to compare the 1999 data to the most recent data despite this admonition, it would indicate a decrease among 12-17 year olds from 10.3 to 9.08%.