A recent study reveals that high potency cannabis can leave a specific mark on DNA, shedding light on its biological effects.
New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London and the University of Exeter suggests that the use of high potency cannabis results in a unique mark on DNA.
Published in the journal Molecular Psychiatry, this study is the first to indicate that high potency cannabis can create a distinguishable mark on DNA, thereby offering insights into how cannabis impacts biological functioning. High potency cannabis is defined as having a Delta-9-tetrahydrocannabinol (THC) concentration of 10 percent or higher.
The findings also indicate that the influence of cannabis on DNA differs between individuals experiencing their first episode of psychosis and those without any history of psychosis. This suggests the potential for DNA blood tests to identify cannabis users at risk for developing psychosis, which could pave the way for preventive measures.
The research was supported by the Medical Research Council, the National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre (BRC), and the NIHR Exeter BRC.
Marta Di Forti, the study’s lead author and Professor of Drugs, Genes and Psychosis at King’s IoPPN, stated: “As cannabis use becomes more prevalent and high potency varieties are increasingly accessible, it is vital to comprehend its biological effects, particularly concerning mental health. Our study is the first to illustrate that high potency cannabis leaves a unique trace on DNA associated with immune system mechanisms and energy production. Future research should investigate whether this DNA signature can help pinpoint cannabis users most likely to develop psychosis, in both recreational and medical contexts.”
The study examined how cannabis affects DNA methylation—a chemical change in blood samples that modifies gene activity by turning genes on or off. DNA methylation represents an epigenetic alteration, meaning it impacts gene expression without altering the DNA sequence, and it plays a crucial role in the relationship between risk factors and mental well-being.
The expert team at the University of Exeter conducted thorough analyses of DNA methylation throughout the human genome, using blood samples from 682 participants, including those who experienced first-episode psychosis and those who have never had psychotic symptoms. The researchers looked into current cannabis consumption, focusing on frequency and potency.
Results indicated that frequent users of high-potency cannabis exhibited changes in genes related to mitochondrial function and immune response, especially the CAVIN1 gene, which may influence energy metabolism and immune reactions. These alterations could not be attributed to the recognized effects of tobacco on DNA methylation, which is normally present in the joints of many cannabis users.
Dr. Emma Dempster, Senior Lecturer at the University of Exeter and the first author of the study, commented: “This is the first research to demonstrate that regular use of high-potency cannabis creates a distinct molecular imprint on DNA, mainly influencing genes tied to energy and immune function. Our results provide crucial insights into how cannabis usage may modify biological processes. DNA methylation acts as a bridge between genetic and environmental factors, allowing external influences, such as substance use, to impact gene activity. These epigenetic modifications, driven by lifestyle choices and exposures, provide important perspectives on how cannabis use could affect mental health through biological mechanisms.”
Dr. Dempster conducted a meta-analysis combining data from two study groups: the GAP study, including patients with a first episode of psychosis from South London and Maudsley NHS Foundation Trust, and the EU-GEI study, which included both first episode psychosis patients and healthy controls across several countries, including England, France, the Netherlands, Italy, Spain, and Brazil. This resulted in 239 first episode psychosis participants and 443 healthy controls with available DNA samples from both cohorts.
Most cannabis users in the study reported using high-potency cannabis more than once a week (classified as frequent use) and had their first cannabis experience at an average age of 16. High potency cannabis is defined as having a THC content of 10 percent or above, with THC being the primary psychoactive compound in cannabis.
