Cannabis legalisation not linked to increase in youth substance use – study

The legalisation of cannabis in the US, and subsequent rise in sales, have not contributed to an increase in substance misuse among adolescents, a new study has found.

Researchers from Boston College have used the most recent data on adolescent substance use to evaluate the effect of recreational cannabis legalisation and retail sales on youth’s use of cannabis, tobacco, and alcohol.

The findings, reported in the Journal of the American Medical Association (JAMA) Pediatrics, show that although recreational cannabis legalisation has passed in nearly half of US states since 2012, and retail sales of products has risen, there is no evidence that these two factors have contributed to a net increase in substance use among adolescents.

The study authors, Rebekah Levine Coley, a Lynch School of Education and Human Development professor, School of Social Work Professor Summer Sherburne Hawkins, and Christopher F. Baum, chair of the Economics Department, are among the first to evaluate associations between recreational cannabis legislation and recreational cannabis retail sales through 2021.

Since 2012, 24 states and Washington, D.C. enacted recreational cannabis legislation, and 18 states implemented recreational cannabis sales.

The researchers analysed data from nearly 900,000 high school students in 47 states over a 10-year period between 2011-2021.

According to the Pew Research Center, 54% of Americans live in a state where the recreational use of marijuana is legal, while 74% live in a state where marijuana is legal for either recreational or medical use.  

As of February 2024, there are nearly 15,000 cannabis dispensaries operating in the US, with 79% of Americans now living in a county with at least one dispensary.

According to the researchers, recreational cannabis legalisation was associated with modest decreases in cannabis, alcohol, and e-cigarette use, while retail sales were associated with lower e-cigarette use, and a lower likelihood, but also increased frequency of cannabis use among youth consumers, leading to no overall change in cannabis use.

“Although studies of early-enacting states and Canada reported few effects of recreational cannabis legislation on adolescent substance abuse, experts have highlighted the need to further assess policy outcomes in youth as legislation and retail availability spread, and other policies targeting youth substance use shift,” the authors said. 

“We found limited associations between recreational cannabis legalisation and retail sales with adolescent substance use, extending previous findings.”

They noted: “The results suggest that legalisation and greater control over cannabis markets have not facilitated adolescents’ entry into substance use.”

Read the full paper here