Research from King’s College London indicates that several molecular pathways may help explain how heavy cannabis use can be associated with psychosis. These findings, published in Biological Psychiatry Global Open Science, could potentially support earlier risk detection and the development of more targeted interventions for individuals experiencing psychosis in the context of cannabis use.
While previous studies have suggested an association between cannabis use and an increased risk of psychotic disorders, the specific biological mechanisms involved have remained an area of ongoing investigation. This study aimed to delve deeper into the biological relationship between cannabis use disorder (CUD) and psychosis by analysing extensive genetic data.
Investigating the Biological Relationship
The research team at King’s Institute of Psychiatry, Psychology & Neuroscience (IoPPN) conducted a meta-analysis using updated genome-wide association data. They combined cases of schizophrenia and bipolar I disorder into a broader category of psychosis, designed to more accurately reflect patterns of cannabis-related psychosis observed in epidemiological studies.
Key findings from their analysis include:
- Identification of over 500 genetic loci associated with psychosis, with 122 of these being previously unreported.
- A greater than expected overlap between biological pathways linked to psychosis and cannabis use disorder, suggesting a close relationship between the two conditions.
Professor Marta Di Forti, a senior author of the study and professor of drug use, genetics and psychosis at King’s IoPPN, highlighted the importance of these findings. She noted that as discussions around cannabis use continue, there is an increasing need to identify those most vulnerable to potential harms from heavy use and to develop tailored support for individuals who have experienced psychosis linked to cannabis use.
Bidirectional Association and Genetic Variants
The study supports previous evidence of a bidirectional association, meaning that psychosis may influence cannabis use, and cannabis use may influence psychosis. Importantly, the researchers observed a larger magnitude of association from cannabis use disorder to psychosis.
The team identified three distinct groups of genetic variants that may be involved in the pathway from cannabis use disorder to psychosis. These include genes associated with neurodevelopment and neuronal signalling. These findings may offer insights into why some individuals appear more susceptible to psychotic disorders associated with cannabis use than others.
Professor Di Forti explained that these findings could potentially illuminate how cannabis use may be associated with psychosis. She added that only one group of genetic variants was identified from psychosis to CUD, suggesting less variation in how psychosis might be associated with heavy cannabis use, which aligns with clinical observations.
The Role of Glutamate
The research also highlighted the possible involvement of glutamate-related genes in predicting psychosis risk among individuals who use cannabis. Glutamate is a neurotransmitter system known to be affected by THC, the primary psychoactive compound found in cannabis.
Dr. Isabelle Austin-Zimmerman, a research associate at King’s IoPPN and the study’s first author, commented that the findings reveal the biology linking cannabis use and psychosis is complex and may operate through multiple mechanisms. She suggested this represents a step towards understanding potentially different etiologies in psychosis with and without cannabis use.
In time, these insights could provide the foundation for prediction models to identify individuals most at risk, and inform the development of new, targeted interventions, as Professor Di Forti suggested.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Hemp Gazette does not provide medical recommendations, diagnoses, or treatment plans. Always consult a qualified healthcare practitioner before making any decisions regarding your health or any medical condition. Statements concerning the therapeutic uses of hemp, cannabis, or cannabinoid-derived products have not been evaluated by Australia’s Therapeutic Goods Administration (TGA). Medicinal cannabis products in Australia are accessed via prescription pathways under TGA regulation.
