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States With Legal Marijuana Have Less Underage Use And Impaired Driving Than Criminalized States, Study Shows



States where marijuana is still criminalized see people initiate cannabis use at a younger age, consume more frequently and drive while under the influence more often, according to a new, large-scale survey from a marijuana policy consulting firm.

Cannabis Public Policy Consulting (CPPC) analyzed a wide range of marijuana use trends and public health outcomes in 25 states—including those where cannabis is completely prohibited, where only medical marijuana is allowed and where adult-use is legalized.

The overall findings support the idea that regulated markets promote more responsible behavior and “encourage positive cannabis-related outcomes to public health,” the CPCC paper says.

(Disclosure: CPPC supports Marijuana Moment’s work through a monthly pledge on Patreon.)

For example, the survey found looked at the age of initiation for marijuana use, which is considered a key data point considering that the younger a person starts to consume cannabis or other drugs, the more likely it is that they will experience “negative short-term and long-term health outcomes, and societal consequence.”

The average age of initiation in illicit states is 16.7 years old, compared to 17 years old for both medical and recreational states. That difference may seem nominal, but as the researchers pointed out, “the difference of approximately four months earlier initiation of cannabis use in illicit states could very well represent a critical part of” youth development.


In any case, it shows that legal marijuana access for adults in states that have it is not leading to young people initiating cannabis consumption at an earlier age.

“The finding that those in adult use states show a higher average age of initiation is important as it indicates that regulated access of cannabis is not expediting cannabis use among youth,” the study says.

Another key finding concerns frequency of use among those aged 16-20. Consistent with the initiation result, young people living in illicit states tend to use marijuana more frequently, at 13.6 days per month on average. That’s nearly double the 7.9 days per month average for medical cannabis states and also higher than the 9.5 days per month observed in adult-use states.


“Together, youth and young adults in both medical and adult use states averaged about five days less of cannabis use compared to those in illicit states,” it says. “This difference equates to an estimated sixty days more cannabis use in illicit relative to legal states on average each year.”

“The age of cannabis use initiation for illicit states (≈16 years old) aligns well with this finding when contextualized within the snowball effect, where earlier age of initiation increases the risks of future cannabis use. As such, these two findings are unlikely to be coincidental, and their co-occurrence is to be expected along with negative public health consequences.”

The survey also examined rates of cannabis use disorder (CUD), which is defined as having two or more symptoms on a list of criteria that includes difficulty controlling or reducing marijuana use, experiencing withdrawal symptoms, trouble maintaining relationships and continuing to use despite negative consequences.

The CUD score was statistically the same on average across states with all three legal statuses, though illicit states saw a marginally higher score of 2.3, compared to 2.2 in medical states and 2.1 in recreational states.


In fact, CPPC’s Regulatory Determinants of Cannabis Outcomes Survey (RDCOS) found that “there were no differences observed among the three state legalization statuses in terms of overall cannabis prevalence, cannabis use disorder (CUD) prevalence, and overall health status.”

One of the key concerns expressed by skeptics or opponents of legalization is the potential impact on highway safety, with those who are against the reform arguing that providing regulated access would lead to more impaired driving. The survey contradicted that argument as well.

It determined that people living in illicit states reported driving under the influence the most, at 5.1 days per month on average. In medical states, that rate was 4.2 days per month; in adult-use states, it was 4.3 days per month.


“When multiplied by twelve months and scaled to population levels at ages 16 and older, the difference of .85 fewer days of DUIC per month represents tens of millions of instances of DUIC each year across the United States,” the RDCOS found.

“The findings of this report provide one of the largest and most comprehensive studies to date examining potential differences in cannabis-related public health outcome as a function of state-level legal cannabis status,” it concludes. “Given that this is not a causal analysis, the current findings will need to be replicated and extended using both cross-sectional and longitudinal studies that identify and compare the impacts of legalization across time.”

The survey involved an analysis of data collected in August from 25 states, involving 5,000 U.S. residents. It’s the first report from a multi-part data collection effort that the firm hopes will inform public policy decisions with “the most up-to-date inferential analysis of cannabis policies and outcomes.”

CPPC Director Mackenzie Slade called the study “groundbreaking.”

“For the first time, we have scientific data that shows cannabis legalization could have a positive impact on public health,” she said in a press release.

A CPCC staffer told Marijuana Moment that “our plan is to continue to run this quarterly, with the next rounds capturing all 50 US states.”

The current report says that the information provided by the surveys can help to shape better policies.

“Given the data deficit pervasive to the cannabis policy field, legalization efforts have often forced the implementation of policies that are not data-informed, but rather grounded in the principles of harm reduction,” it says. “This fact, coupled with the findings presented here, show considerable promise for future data-driven legal cannabis policies to provide net wins to cannabis public health outcomes in addition to existing gains in social equity, criminal expungement, and economic conditions.”

This analysis comes on the heels of the latest federally funded Monitoring the Future (MTF) Survey, which found that teen cannabis use remained stable in 2022—even as more states legalized marijuana and society started to return to normal following the worst of the coronavirus pandemic by lifting restrictions that kept many students at home under parental supervision.

While it might be somewhat surprising that young marijuana use didn’t increase after pandemic restrictions were lifted as some expected, the general finding that teen consumption is stable is consistent with a growing body of scientific literature on the topic.

Just last month, for example, another NIDA-funded study that was published in the American Journal of Preventive Medicine found that state-level cannabis legalization is not associated with increased youth use.

The study demonstrated that “youth who spent more of their adolescence under legalization were no more or less likely to have used cannabis at age 15 years than adolescents who spent little or no time under legalization.”

Yet another federally funded study from Michigan State University researchers that was published in the journal PLOS One this summer found that “cannabis retail sales might be followed by the increased occurrence of cannabis onsets for older adults” in legal states, “but not for underage persons who cannot buy cannabis products in a retail outlet.”

New Jersey Adult-Use Marijuana Sales Jumped In Latest Quarter, Topping $100 Million For First Time, State Reports

Photo courtesy of Chris Wallis // Side Pocket Images.

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