Study: 19 Is Ideal Age Limit For Legal Cannabis Access

A study by researchers at Memorial University of Newfoundland, Canada suggests that the legal age for cannabis use should be set at 19, according to a MedicalXpress report. The authors found that setting a consumption age at 19 could diminish some potential adverse health effects, such as smoking and negative mental health outcomes.

The study used data from Canada’s Tobacco Use Monitoring Surveys and Tobacco, Alcohol and Drugs Surveys conducted between 2004 and 2015. Those surveys annually interview up to 20,000 individuals aged 15-and-older.

For smoking, respondents who first used cannabis when they were 19 or 20-years-old were less likely to smoke cigarettes later in life than those who first used cannabis at 18 but no difference was found for those who started using cannabis after 19, suggesting an optimal legal cannabis consumption age of 19.

While general health was better among those who started using cannabis at age 18, relative to those who started before 18, no significant difference was found among those who started after that age, suggesting a minimum legal age of 18. However, mental health outcomes were found to be better among those who first used cannabis aged 19 to 20 than before age 18, also suggesting a minimum legal age of 19.

The number of respondents who reported a high level of completed education was 16 percent higher among those who first used cannabis between the ages of 21 and 24, relative to those who first used it before age 18, which suggests an optimal minimum legal age of 21.

Dr. Hai Nguyen, lead author of the study, said that “keeping the legal age below 21 may strike a balance between potential increases in underground markets and illegal use, and avoiding the adverse outcomes associated with starting to use cannabis at an earlier age.”

“Prior to legalization, the medical community recommended a minimum legal age of 21 or 25 for non-medical cannabis use in Canada. This recommendation was based on scientific evidence around the potential adverse impacts of cannabis on cognitive development. However, policymakers feared a high minimum legal age may lead to large underground markets, with those under the legal age continuing to use cannabis illegally. Ultimately, a lower legal age of 18 or 19 was decided across provinces, however, there remains ongoing debate and calls to raise the legal age to 21.” – Nguyen in the study via MedicalXpress

The Canadian health survey uses self-reported data, which the authors cautioned may not be totally accurate because they require participants to recall when they first used cannabis and the data was collected prior to cannabis legalization in the nation, which could have led some respondents to misrepresent their history in the survey. They suggest further research is needed to establish potential causal effects between the age at which cannabis is first used and the outcomes measured in the study, and on additional outcomes such as driving behaviors and other drug use.

The study was published in the journal BMC Public Health.