Cannabis Use and Internalizing/Externalizing Symptoms in Youth: A Canadian Population-Based Study

Journal of Adolescent Health

A study of Canadian adolescents found an association between cannabis use and the symptoms of psychiatric conditions such as anxiety, depression, conduct disorder, and attention deficit hyperactivity disorder (ADHD). Data was collected from almost 11,000 Ontarians aged 12-17.

Adolescent males who used cannabis one or more times per week had about twice the odds of expressing elevated symptoms of anxiety and depression compared to their peers who did not use cannabis. Comparatively, adolescent females who used cannabis one or more times a week had over three times greater odds of expressing elevated symptoms of anxiety and depression compared to their peers who did not use cannabis. The researchers considered the 20% of participants with the highest levels of anxiety and depression to have “elevated symptoms”.

As for symptoms of conduct disorder and ADHD, male frequent cannabis users had about two times greater odds of these symptoms, and female frequent users had around five times greater odds than their non-using peers. Using cannabis twice a month or less was also associated with elevated symptoms, but to a lesser degree than weekly cannabis use.

These results account for differences in age, smoking, binge drinking, positive parenting, and negative/ineffective parenting. In this dataset, factors such as bullying, being born outside of Canada, household income, physical activity, and living in a single-parent household were not systematically different between cannabis-using and non-using participants.

The study strengths include the large representative sample and that adolescents answered questionnaires alone on a computer, which increases the likelihood of honest reporting. Limitations include the self-reported nature of the data and that it was collected at only one time point. This makes it difficult to assess whether cannabis use causes symptoms, symptoms cause cannabis use, or neither. The researchers point out that other studies suggest that adolescents may use cannabis to self-medicate the symptoms of depression, anxiety, and ADHD.

For the original article, click here.

Girgis, J., Pringsheim, T., Williams, J., et al. Cannabis Use and Internalizing/Externalizing Symptoms in Youth: A Canadian Population-Based Study. Journal of Adolescent Health.  Published: January 4, 2020. https://doi.org/10.1016/j.jadohealth.2020.01.015.