Reviewed by Stacey McKenna, PhD

According to a 2015 study by Saloner et al., cannabis use can have much more serious consequences for youth than their adult counterparts, including “cognitive decline, poor educational achievement, mental illness in adulthood, and injury and death caused by marijuana-impaired driving.” As such, there has been considerable debate among pediatricians and researchers about the best way to approach regulation.

Citing concerns that prohibition-ending policies would normalize consumption, reduce perceived risk and make the substance more accessible for young people, the American Academy of Pediatrics (AAP) has consistently opposed the legalization of recreational cannabis. However, other experts have recommended four priorities that they posit “could help advance the AAP’s goals of protecting child and adolescent health” within the context of legalization. Two of these recommendations would restrict marketing in order to limit youth exposure and closely regulate packaging to minimize risk of accidental consumption. The other two—taxation to keep legal and black market prices high, and tight retail rules and monitoring that strictly enforce age restrictions—focus on reducing youth access to cannabis via regulation.

However, in a Research Letter published this past July in the Journal of the American Medical Association, Anderson et al. challenge the assumption that cannabis legalization will necessarily lead to increased consumption among young people by briefly outlining findings from their systematic study that examined how two forms of cannabis regulation—medical or recreational laws—affected youth consumption rates. It analyzed 24 years of Youth Risk Behavioral Survey (YRBS) data (from 1993 to 2017), for a sample size of 1,414,826, and data from survey results were adjusted for states that had recreational or medical cannabis regulations. In so doing, the authors looked at two outcome measures: likelihood of any cannabis use in the last 30 days and frequent use (10 days or more) over that same period.

The study found no significant association between youth cannabis consumption and legalization for medical purposes. And things were even more interesting with respect to their findings about recreational legalization, as the massive study indicated that legalizing recreational use might actually contribute to a decrease in youth use. In fact, the researchers found substantial and statistically significant decreases in the odds of cannabis use (down 8 percent) and in the odds of frequent cannabis use (down 9 percent) in the years after legalization, as compared to those before.

While this study is similar to others that have found no association between medical cannabis legalization and likelihood of youth consumption, findings on the relationship with respect to recreational youth consumption have been mixed. Some studies have indicated that youth might be more likely to use cannabis after recreational legalization, some have found mixed associations (for example, no relationship between recreational legalization and youth use in Colorado but a slight positive correlation in Washington) and others have shown a decrease in the likelihood of youth consumption. Given such varying results, Anderson et al. adds a massive and important data set to the current body of research on the effects of recreational cannabis legalization.

What’s more, these findings could even be underestimating the reduction because surveys such as the YRBS may have been especially prone to underestimating real use prior to legalization. To this point, a 2018 retrospective study of cannabis use before and after recreational legalization in Washington State found a much smaller increase in use (1.2 percent) compared to previous prospective research on the topic (3.8 percent). It has thus been suggested that this might be due to a reduction in stigma post-legalization that would make respondents more likely to report both current and past cannabis consumption.

As more states move away from outright prohibition and toward some form of regulation, and with federal regulation likely in the coming years, evaluating how forms of legalization may adversely impact public health, including potential increases in youth use is of the utmost importance.

As such, findings such as Anderson et al.’s suggest that, done right, legalization may, in fact, reduce both the harms associated with youth cannabis consumption (such as criminal conviction), and the likelihood of that consumption altogether. In fact, Anderson and colleagues point to a 2012 Huffington Post article that argues that prohibition has failed where legalization and regulation of cannabis through licensed dispensaries might succeed.

Accordingly, this study’s findings are not only important for rounding out existing understandings of the relationship between recreational cannabis legalization and youth consumption, but they also fit well with the suggestions made by Saloner et al. for building regulations into legalization.

As with any research seeking to glean the real impact of a policy on a population, these findings cannot definitively demonstrate that legalization of cannabis is what led to the reduction in odds for youth consumption. However, the data support the value of continued research and the importance of using such research in policy development.