Legalization of cannabis associated with rising use among adolescents

A study in the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP), published by Elsevier reports that the legalization of recreational cannabis in various states in the US has resulted in an increased likelihood of cannabis use in the past month among adolescents and young adults.

Cannabis use for medical purposes has been legalized in 38 states, while 24 states have legalized cannabis for recreational purposes for those above 21 years of age. Previous meta-analytic studies have shown that legalization of cannabis for medical use did not have a significant effect on the prevalence of cannabis use in youth. However, the results regarding the effects of recreational cannabis laws have been inconclusive due to the small number of states with recreational cannabis laws included in prior meta-analyses. With an increasing number of states legalizing recreational cannabis, it has become imperative to assess the effect of legalization on youth cannabis use. Studying the effects of legalization of cannabis use can provide a basis to devise preventative measures aimed at reducing the risks associated with cannabis use on the developing brains of adolescents and young adults in the United States.

This meta-analytic review, led Dr. Aditya Pawar, identified 4,604 citations, of which the authors systematically reviewed and meta-analyzed thirty studies that provided quantitative data showing the effects of cannabis legalization amongst adolescents and young adults. Included studies mostly utilized large datasets from nationwide surveys, and had compared the past month cannabis use between states with and without cannabis legalization. The authors found that recreational cannabis legalization was associated with a significant increase in cannabis use, with the effect being more pronounced in young adults. Limiting the analysis to more recent studies also showed a small, but significant, increase in cannabis use amongst adolescents as well.

In discussing the findings of this meta-analysis, Dr. Pawar states, "Cannabis use, especially frequent and high-potency cannabis use can severely affect neurodevelopment among adolescents and early use increases the chances of dependent use among young adults. Increasing trends towards legalization can potentially decrease the perceived risk of harm leading to an increased cannabis use. Evidence base showing an increase in cannabis use among youth should help public and policy makers use preventative measures including but not limited to public education, devising appropriate regulations in the laws such as regarding the potency and availability of cannabis, and increasing availability of evidence based early interventions."

The authors conclude that this meta-analysis emphasizes the need to further assess the benefits and harms that cannabis legalization may have on the youth in the US considering an increase in youth cannabis use.