Cannabis use rises in adolescents hospitalised with mental illness

There has been a rise in cannabis use among adolescents hospitalised with mental illness since the decriminalisation of cannabis in South Africa in 2017, a recent study by the University of Cape Town’s Department of Psychiatry and Mental Health revealed.

The study, led by Dr Michelle Swartz, analysed the clinical records of 266 adolescents hospitalised between April 2015 and March 2019. It found a 3.7% increase in cannabis use post-decriminalisation, with a higher proportion of users presenting with co-occurring psychotic disorders and cannabis use disorders.

“I found that cannabis was the most reported substance used both pre- and post-ruling, with a 3.7% increase in adolescents who smoked cannabis post-ruling,” said Swartz.

This, she said, aligned with the World Drug Report of 2023, which noted a 21% increase in annual cannabis users over the past decade.

“There was a notable increase in hospitalisations due to cannabis use disorders, attributed to greater acceptance, higher potency, increased frequency of use and legislative changes related to cannabis. Despite an increased proportion of females using cannabis post-ruling, I found that the majority of cannabis users were male,” said Swartz.

“Additional key findings in this study included findings that trauma was a significant stressor for cannabis users regardless of the timing of the legal ruling, with a higher proportion of post-ruling patients reporting trauma, including physical, verbal, sexual abuse and neglect. This aligns with findings from a Cape Town study linking childhood abuse to increased substance use.”

The study underscores the vulnerability of adolescents to the effects of cannabis and calls for further research, awareness, and targeted interventions in light of the evolving legislation.

“While the findings in this study are limited to a specific hospital in the Western Cape, it does highlight the need for ongoing research involving adolescents, their risks for mental illness and the impact of substance use particularly cannabis given the changing legislation in South Africa. It also emphasises the need for more adolescent focused awareness and prevention strategies, interventions and services,” she said.

The Mercury