Cannabis Use Among Students in Grades 8, 10, and 12, by Sex — King County, Washington, 2008–2021

Discussion

During 2008–2021, in addition to overall decreases in cannabis use among students in grades 8, 10, and 12 in King County, Washington, a narrowing and possible reversal of sex-based differences in current cannabis use was observed. These reported recent decreases in cannabis use among students in grades 8, 10, and 12 are consistent with overall statewide trends (8) and sex-stratified trends in national data showing larger decreases among male students (7).

Decrease in Cannabis Use

The observed overall decreases in cannabis use among students in grades 8, 10, and 12 might be associated with changes in the availability of cannabis among persons aged ≥21 years as well as limited opportunities to engage in use. The period 2012–2014 includes the legalization of nonmedical cannabis in Washington in 2012. Researchers studying the association of cannabis laws with cannabis use among high school students (grades 9–12) have observed similar declines in cannabis use after legalization of nonmedical cannabis (9). The legalization of nonmedical cannabis for adults aged ≥21 years in Washington with licensed dispensaries requiring proof of age might have affected availability of cannabis to younger persons as well as their opportunities to engage in its use. This, in turn, might have had an impact on use prevalence. The period 2018–2021 also included the unexpected shift to remote learning environments in 2020 associated with the COVID-19 pandemic. With increased time spent at home, students might have been subject to increased parental supervision, which could deter substance use, including use of cannabis. Increased parental supervision could have been compounded by limited access to cannabis, if a main source was from friends or social settings away from the home.

Sex Differences in Cannabis Use

Shifts in sex-specific differences in cannabis use raise questions about underlying factors and potential implications for prevention and use reduction strategies for youths. One explanation for diminishing sex-specific differences might be related to a previous focus on higher prevalence users. For example, interventions might have been most effective among males because of their higher use prevalences. A second explanation might be related to evolving social norms regarding cannabis use. Among adolescents, a positive association between cannabis use and norms surrounding its use has been established (2). However, whether the strength of the association has changed over time, varies by sex, or has become stronger for females than for males is unclear. Future studies might examine trends in cannabis use norms by sex, and the association between norms and cannabis use by sex.

Limitations

The findings in this report are subject to at least four limitations. First, because cannabis use was self-reported, use might have been underreported (e.g., because of legal implications). To mitigate this potential bias, the Healthy Youth Survey was administered during structured classroom time in a test-like environment, and no identifying information was collected (10). Second, this report relied on self-reported sex assigned at birth to categorize students by sex and does not include students who identify as transgender or nonbinary. The Healthy Youth Survey introduced gender identity questions in 2018; thus, examining trends by gender identity was not possible. Third, this report provides trends in prevalence of cannabis use among King County students in grades 8, 10, and 12, and was not intended to identify contextual factors that might have influenced cannabis use estimates (e.g., legalization or the COVID-19 pandemic). Finally, findings do not necessarily apply to students who are not in grades 8, 10, and 12 enrolled in King County, Washington public schools.

Implications for Public Health Practice

Although downward trends in cannabis use among King County students in grades 8, 10, and 12 are encouraging, continued monitoring is necessary to better understand longer-term effects of social phenomena, including cannabis legalization and pandemic-related disruptions, and to assess whether observed decreases are sustained. It is important for monitoring to prioritize identifying differences across demographic characteristics, including sex or gender identity, which can potentially support the development of tailored interventions and ensure equity in programmatic cannabis use reduction and prevention measures. Lastly, whereas the focus of the present analysis was on sex, future analyses could explore potential variations across additional demographic variables including race, ethnicity, or socioeconomic status.