Cannabis Use Linked to Earlier Onset of Psychosis Even in Adults

August 25, 2026 Dr. Michael Lee – Health Editor Health

People who use cannabis in their 20s and 30s are developing psychosis years earlier than non-users, according to a study published in Biological Psychiatry. The study, which examined 149 studies involving more than 71,000 people, found that cannabis users who developed psychosis aged 30 or over had an onset of more than 6.3 years earlier on average.

Cannabis Use Linked to Earlier Psychosis Onset in Young Adults, Study Finds

Key Clinical Takeaways:

  • Cannabis use in people who developed psychosis aged 30 or over is associated with an earlier onset of psychosis by more than 6.3 years.
  • The research found no evidence of earlier onset of psychosis for people who developed it under 20.
  • THC, the most active ingredient of cannabis, works by locking onto the cannabis receptors, which are part of the brain’s endocannabinoid system.

Study Methodology and Findings

The research analyzed studies involving people with schizophrenia from Europe, North America, and Australia. The study emphasized the role of delta-9-tetrahydrocannabinol (THC) in the brain’s endocannabinoid system.

The research revealed that cannabis use was associated with an earlier age at psychosis onset by 2.5 years on average. For cannabis users who developed psychosis in their late 20s, the onset was 4.4 years earlier on average, and this difference increased to more than 6.3 years in people who developed psychosis aged 30 or over. “This challenges the idea that delaying cannabis use until your mid-20s – when people believe their brain has finished developing – is a safer option to avoid the risks of psychosis,” the authors noted.

Public Health Implications

Psychosis, affecting around 0.5% of Australians, is characterized by reality distortion, hallucinations, and false beliefs. Early onset is associated with worse clinical outcomes, greater functional impairment and struggles with self care.

Cannabis not 'safer' for younger people, linked to early psychosis - 1News
Photo: cedclinic.com

The study’s authors highlighted that cannabis is increasing in potency.

Funding and Transparency

Directory Bridge: Clinical and B2B Resources

Historical Context and Mechanisms

Previous research by the same group in 2011 linked cannabis use to an earlier age of onset of psychosis. This new research clarifies that the difference in onset increased for people who developed psychosis aged 30 or over. The endocannabinoid system, which helps maintain physiological balance by regulating processes including appetite, immunity, memory, mood, pain, sleep and stress responses, is impacted by THC.

Expert Commentary

Future Research Directions

Conclusion

The growing body of evidence underscores the complex relationship between cannabis use and mental health.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider regarding any medical condition, diagnosis, or treatment plan.

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