Cannabis use among hospitalised adolescents before and after decriminalisation in South Africa

Background: Cannabis is the most widely used substance worldwide, and its use is much higher among adolescents. However, adolescents are at higher risk of negative sequelae secondary to this use, including the possible development of mental disorders. On 31 March 2017, the South African High Court ruled that cannabis use by an adult in a private dwelling should be decriminalised. Aim: This study aimed to determine the clinical profile of adolescents who use cannabis, who use, who present to a tertiary hospital in Cape Town, South Africa, before and after the high court ruling in 2017. Setting: Folder review of adolescents admitted at Groote Schuur Hospital (GSH) in the Emergency Psychiatric Unit. Methods: This study was a retrospective folder review of adolescents admitted from April 2015 to March 2019. Results: Cannabis was the most commonly used substance in the study, with increased use seen post-ruling. The most common frequency of cannabis use reported was daily. A significantly higher proportion of patients who used cannabis pre-ruling had psychotic disorder (p p < 0.001) and cannabis use disorder (p p = 0.01). Post-ruling, the results were statistically significant (p p < 0.001) for both. Conclusion: The study showed an increasing prevalence of cannabis use in adolescents admitted with mental illness after the high court ruling in 2017. This study also demonstrates that adolescents remain a vulnerable population to the effects of cannabis and highlights the need for further research. Contribution: The findings of this study call for more focussed adolescent interventions and services.