The adoption of statewide laws regulating the sale of marijuana products to adults is not associated with any increase in cannabis initiation among people under the age of 21, according to data published in the journal PLoS One.
Researchers affiliated with Michigan State University assessed marijuana use trends in a nationally representative cohort of subjects in order to evaluate whether or not legalization was associated with any changes in the percentage of people initiating cannabis use for the first time.
Investigators identified an increase in the number of new adult cannabis consumers following legalization, but they reported no changes among those under 21 years of age.
They reported: “These results show consistent evidence of an increase in the occurrence of newly incident cannabis use for adults aged 21 years and older after the removal of prohibitions against cannabis retail sales. For those aged 12-20-years-old, the study estimates support the hypothesis that RCLs [recreational cannabis laws] did not affect the occurrence of newly incident cannabis use for underage persons.”
The findings are consistent with those of prior studies reporting that adult-use legalization is not associated with either increased use or access among young people.
“Cannabis policy liberalization continues to be a contentious issue in the national political landscape. … Policymakers and the voters who elect these policy-makers cannot make the best judgments in the absence of evidence, unless their decisions are to be based on potentially erroneous prejudices or beliefs,” authors concluded. “The evidence from this study is not perfect, but the estimates provide an evidence base that can be judged in relation to an important question – namely, should we worry about underage cannabis use when adults are allowed to buy cannabis products in retail shops? And might the occurrence of adult-onset newly incident cannabis use increase if this policy change is made? The answer to the first question at this point seems to be that there has been no policy influence on cannabis incidence in the underage adolescent population after adults have been allowed to buy cannabis in retail shops. The answer to the second question at this point indicates a tangible uptick in the occurrence of newly incident cannabis use among adults who otherwise might never have tried cannabis. We are hopeful that voters, policymakers, and public health officials can use this evidence as they forecast what might change if cannabis policies are liberalized to permit adult purchases from retail cannabis shops in their jurisdictions.”
Full text of the study, “Estimating the effects of legalizing recreational cannabis on newly incident cannabis use,” appears in PLoS One. Additional information is available from NORML’s fact sheet, “Marijuana Regulation and Teen Use Rates.”