Associate Professor Janni Leung is a Research Fellow at The University of Queensland, Australia. She studies the epidemiology of substance use and mental health. Much of her work involves conducting systematic reviews, meta-analyses, and applying statistical models to epidemiological data on addiction and mental health issues to better understand their impacts on populations.

Abstracts

Co-occurring mental health and substance use problems in people with gaming disorder – Findings from The International Gaming Study (‘Mental health, decision making, and addiction mechanisms’ session)

Aims: Gaming disorder may co-occur with mental health problems and substance use problems, but evidence remains limited. We examined the association between gaming disorder risk and mental health, and substance use indicators in a multi-country sample of regular gamers.

Methods: Data were from the International Gaming Study 2024, a cross-sectional online survey across Australia, China, Indonesia, Netherlands, USA with 1524 adult participants (48.6% women; mean age 34.8 years) from the general population who played video games at least three hours per week. We analysed gaming disorder with depression, anxiety, ADHD, and daily or near daily use of substances.

Results: Compared with the no/low-risk gaming disorder group, those with higher-risk gaming disorder had a significantly higher odds of depression (OR=4.44, 95%CI [3.35-5.89]), anxiety (OR=3.33[2.51-4.40]), and ADHD (OR=6.58[4.89-8.87]). The higher-risk gaming disorcer group also had a significantly higher odds for daily or near daily use of alcohol (OR=3.19[2.41-4.22]), nicotine products (OR=3.25[2.44-4.31]), cannabis (OR=4.47 [3.29-6.07]), benzodiazepines (OR=9.80[6.99-13.74]), caffeine (OR=2.47[1.83-3.34]), prescription stimulants (OR=6.55 [4.83-8.89]), and other stimulants (OR=7.64[5.52-10.59]).

Conclusions: In this multi-country community sample of regular video gamers, individuals with higher gaming disorder risk had a substantially higher odds of co-occurring mental health and substance use problems. These findings support routine screening for mental health and substance use among individuals at risk of gaming disorder and highlight the need for integrated prevention and intervention strategies addressing multiple risk behaviours.

Cannabis use and mental disorders: assessing the coherence of evidence from studies across different methodologies (Lancet Psychiatry Commission on Cannabis)

Cannabis use often begins in adolescence and young adulthood, when mental disorders, such as anxiety, depression, psychosis, and bipolar disorder typically also first develop. Young people who use cannabis daily, or near daily, and develop a cannabis use disorder have a higher prevalence of these mental disorders. We assessed the coherence of evidence from epidemiological, genetic, experimental, and preclinical studies on relationships between frequent cannabis use and the increased incidence, prevalence, and persistence of psychosis, bipolar disorder, anxiety, depression, and suicidal behaviours. We found credible evidence that cannabis use is a contributory cause of psychosis. There were fewer high-quality epidemiological and genetic studies of bipolar disorder. The role of cannabis use in depression, anxiety, and suicidality was less certain because associations were modest and could also reflect self-medication, shared risk factors, or bidirectional relationships. Taken together with lived experience advice and the common comorbidity, a high priority should be given to effective interventions for addressing both cannabis use disorders and mental disorders.