Cannabis use among adolescents among young people in postcodes with medical clinics
More than ten years after the first US states began legalizing recreational cannabis and nearly thirty years after California became the first state to legalize medical cannabis, opponents continue to argue that the increase in the number of dispensaries will lead to an increase in cannabis use among young people. While previous studies have already shown that this argument does not hold water, recent research provides even more evidence.
According to one survey published in the journal Cannabis, there is no evidence of an increase in cannabis use among young people living in ZIP (area improvement plan) codes where there are operating medical dispensaries.
Researchers from the University of Illinois led this study, titled "Adolescent Cannabis Use Among Youth in ZIP Codes with Medical Dispensaries," and examined the relationship between adolescent cannabis use and adolescent cannabis use clinics. Status over a three-year period.
“The question of whether liberal policies lead to a increase in cannabis use among adolescents remains of concern," the authors state in the study's abstract. “To date, there is little evidence that the prevalence of cannabis use among adolescents statewide has increased in states where policies are liberalized. However, analyzes at the local level show some negative impacts. We therefore analyzed whether living in a postal code with a dispensary (ZCWD) was associated with cannabis use among adolescents.”
The authors highlight two factors that may have an impact on substance use among adolescents living in a ZCWD.
The first is ease of access, which means supply is high after a dispensary opens in a jurisdiction. However, the researchers also note that with the passage of laws on medical and recreational cannabis, teens' access may actually be declining "due to difficulties in obtaining cannabis from dispensaries rather than from drug dealers," they note. “In other words, if cannabis is legalized and regulated, it may be riskier to sell it to teenagers.
The second factor is the perception of harmfulness, ie adolescents may consider cannabis to be less harmful if sold at a local dispensary. The study points out that trends have shown that the perception of harmfulness is negatively associated with cannabis use among adolescents.
The researchers matched postcodes of dispensaries in public records with postcodes reported in the 2018 survey on Illinois youth, focusing on 8th, 10th, and 12th grades. The team then compared cannabis use over the past 30 days and the past year among young people living in a ZCWD and those not living in a ZCWD. The final analytical sample included 10 surveys containing 569 self-reported postal codes.
The researchers ran models for the entire sample, those who lived and those who did not live in a ZCWD. The study also broke down cannabis use by grade level, noting that cannabis use increases with age.
In the end, 12% of adolescents living in a ZCWD declared having used cannabis in the last 30 days (6,6% of 8th graders, 10,6% of 10th graders and 20,1% of 12th graders) and 15,6% of adolescents not living in a CWDZ (5,2% of 8th graders, 13,7% of 10th graders and 26,4% of 13th graders).
Use in the past year followed a similar pattern with a higher overall rate of cannabis use, with an increase with each subsequent grade level and higher rates of use among adolescents not living in a CWDZ – 18,3% overall among teenagers living in a ZCWD (9,7% of 8th graders, 16,9% of 10th graders and 30,9% of 12th graders) and 22,4% in total among adolescents not living in a CWDZ (8,4% of 8th graders, 20,3% of 10th graders and 36,1% of 12th graders).
"This study showed the association between adolescent cannabis use and the presence of a ZIP code-level dispensary, which may be more accurate than taking the state average for cannabis prevalence, as do national studies,” the authors conclude. “This study found no evidence of an increase in cannabis use among young people living in ZIP codes with active medical cannabis dispensaries. In fact, 12th graders living in ZIP codes with dispensaries used less cannabis in the past 30 days and the past year.
If these results confirm that cannabis reform is not synonymous with increased use among young people, the authors admit that the scope of the study is limited. It focuses only on Illinois, and it's unclear whether ZIP codes are adequate measures of actual clinic proximity, the authors say.
Going forward, the researchers recommend longitudinal studies, more precise proximity measures, and additional tracking of perceived harmfulness and types of cannabis used rather than cannabis use in general.
