Personality disorders linked to cannabis and polysubstance use in young Australians

This study examined personality dysfunction and antisocial traits in 100 young Australians (aged 18-25) receiving treatment for substance use disorders, with a particular focus on understanding the psychological profiles of those seeking residential withdrawal services. The researchers found that nearly half the sample (48%) showed signs of general personality disorder, while 43% met criteria for Antisocial Personality Disorder (ASPD). These high rates suggest that personality dysfunction is extremely common among young people struggling with multiple substance dependencies.

A striking finding was the strong connection between personality dysfunction and polysubstance use—the practice of using multiple drugs simultaneously. Youth with likely ASPD showed particularly strong associations with cannabis use disorder, alongside problematic use of methamphetamine, alcohol, and sedatives. The study also revealed that 59% had prior arrest histories, with 23% reporting 10 or more arrests, indicating significant involvement with the criminal justice system. Additionally, 66% of participants met criteria for two or more concurrent substance use disorders, highlighting the severe and complex nature of addiction in this young population.

The research suggests that addressing personality functioning—not just treating substance dependence alone—may be critical for improving treatment outcomes. The authors recommend integrating personality-informed or schema-focused therapeutic approaches into withdrawal services to better support young people struggling with the intersection of personality dysfunction and addiction. This holistic approach could help break the cycle of polysubstance use and criminal involvement that characterizes this vulnerable population.