New Study Shows Effects of Cannabis on DNA and Provides Insights into Psychosis

A groundbreaking study¹ by the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London, in collaboration with the University of Exeter, has revealed that high-potency cannabis use leaves a distinct mark on DNA, with potential implications for mental health. Published in Molecular Psychiatry, this is the first research to suggest that frequent use of cannabis containing 10% or more THC may alter DNA methylation—a key process in gene regulation—providing valuable insights into the biological impact of cannabis use.

Cannabis and DNA: A Unique Signature

The study’s most striking finding is that high-potency cannabis alters DNA methylation, a process that changes how genes function without altering the DNA sequence itself. This change affects genes associated with the immune system and energy production, particularly the CAVIN1 gene, which could influence how the body responds to immune challenges and manages energy at the cellular level. This “molecular mark” of cannabis use could help researchers understand how lifestyle factors, like substance use, may impact gene expression.

Lead researcher Professor Marta Di Forti explains, “With increasing cannabis use and the availability of higher potency strains, it’s essential to understand its biological effects, particularly on mental health. Our study is the first to show high-potency cannabis leaves a unique signature on DNA related to the immune system and energy production.”

A New Link to Psychosis Risk

The research goes beyond identifying DNA changes in general cannabis users; it also highlights a key difference in people experiencing their first episode of psychosis. The study found distinct DNA methylation patterns in individuals who had used high-potency cannabis and had experienced psychosis compared to those who had used cannabis without any psychotic episodes. This suggests that some users may be more biologically predisposed to psychosis due to cannabis use, paving the way for potential future DNA testing.

Dr. Emma Dempster, the study’s first author, points out, “Our findings offer an important insight into how cannabis may influence mental health through biological pathways. By identifying these epigenetic changes, we could one day develop blood tests to determine which cannabis users are at a greater risk of developing psychosis, both for recreational and medicinal purposes.”

Study Overview

The study analyzed DNA samples from 682 participants, consisting of people who had experienced first-episode psychosis and healthy controls who had never had a psychotic experience. Using blood samples, researchers examined the relationship between cannabis use—particularly the frequency and potency—and DNA methylation across the human genome.

Most of the participants who used cannabis frequently consumed high-potency strains with THC levels of 10% or more, which is considered high potency. Notably, these changes in DNA methylation were not influenced by other factors, such as tobacco, which is often consumed alongside cannabis in joints.

What This Means for the Future of Cannabis Research

The implications of this research could be far-reaching, particularly for mental health care. If further studies confirm that DNA methylation patterns can predict susceptibility to psychosis in cannabis users, a simple blood test could potentially be developed to help identify those at greater risk. Such tests could inform preventive measures, allowing for early intervention in individuals who may be more vulnerable to the psychotic effects of high-potency cannabis.

Furthermore, these findings could reshape conversations around cannabis use, particularly as legalization and the availability of high-THC strains continue to rise globally. For medical cannabis users, this research could help physicians better understand individual risks and tailor treatments more effectively.

This study is a significant step toward understanding how high-potency cannabis interacts with our biology at a genetic level, especially concerning mental health risks like psychosis. As cannabis use becomes more widespread, developing tools to predict and prevent potential harms will be crucial. The discovery of a unique DNA signature associated with cannabis use opens the door to further research and, potentially, a future where DNA testing could help identify who is at risk for adverse mental health effects.

Study Reference:

^{1. Dempster, E. L., Wong, C. C. Y., Burrage, J., et al. (2024). Methylomic signature of current cannabis use in two first-episode psychosis cohorts. Molecular Psychiatry. https://doi.org/10.1038/s41380-024-02689-0}