Cannabis use and its impact on mental health in youth in Australia and the United States : a scoping review

Cannabis is a widely used substance among the youth population, with an estimated 2.8% currently smoking cannabis. Its popularity is growing due to the perception of its harmless nature and lack of dependence. However, this increase in use has been linked to mental health issues, especially since its partial decriminalisation in some part of the United States and Australia. The objective of this scoping review was to investigate the mental health impact of cannabis use among young people in Australia and the United States. A scoping review was conducted according to the Joanna Briggs Institute (JBI) protocol, and articles were searched from ProQuest Central and EBSCO Host (MEDLINE and CINAHL databases). A total of 24 articles were analysed, including systematic reviews, meta-analyses, and cohort, longitudinal, and cross-sectional studies. The findings indicate that cannabis use is associated with depression, psychosis, suicide, cannabis use disorder, dependence, decline in cognitive function, and the development of externalising behaviour, particularly attention deficit hyperactivity disorder. However, the relationship between cannabis use and anxiety is equivocal. Mental health issues were more prevalent with increased frequency, duration, intensity, and type of use. Female, minority, LGBTQI, African American, Aboriginal, and Torres Strait Islander youth and the age of onset of cannabis use were significant factors for the development of mental health problems. The increasing prevalence of cannabis use among high school and college students suggests the need for intervention by teachers, parents, and community health professionals to make them aware of its potential negative mental health outcomes. Moreover, policy-level interventions by the government are required to discourage young people from using cannabis.