High-potency cannabis use linked to epigenetic changes, study suggests

A study published in Molecular Psychiatry is the first to suggest that consuming high potency cannabis leaves a distinct mark on DNA, providing valuable insight into the biological impact of cannabis use. High-potency cannabis is defined as having a Delta-9-tetrahydrocannabinol (THC) content of 10% or more. THC is the main psychoactive constituent of cannabis.

Research has also shown that the effect of cannabis use on DNA is different in people experiencing their first episode of psychosis compared to users who have never experienced psychosis, suggesting that there may be potential for DNA blood testing to help characterize cannabis users at risk of developing psychosis. to inform preventive approaches.

Lead author Marta Di Forti, professor of drugs, genes and psychosis at King’s IoPPN, said: “With the increasing prevalence of cannabis use and the greater availability of high-potency cannabis, there is an urgent need to better understand its biological impact, particularly on mental disorders. health.

“Our study is the first to show that high potency cannabis leaves a unique signature on DNA linked to mechanisms around the immune system and energy production. Future research should explore whether the DNA signature of current cannabis use Cannabis, and particularly that of high-potency types, may help identify users at greater risk of developing psychosis, both in recreational and medicinal use contexts.

Researchers explored the effects of cannabis use on DNA methylation, a chemical process detected in blood samples that changes how genes function (whether turned on or off). DNA methylation is a type of epigenetic change, meaning it changes gene expression without affecting the DNA sequence itself and is considered an essential factor in the interaction between DNA factors. risk and mental health.

The University of Exeter laboratory team carried out complex analyzes of DNA methylation across the entire human genome using blood samples from both people who had experienced a first episode of psychosis and people who have never had a psychotic experience. Researchers studied the impact of current cannabis use, including frequency and potency, on the DNA of 682 participants.

The analysis showed that frequent users of high potency cannabis had changes in genes related to mitochondrial and immune function, particularly the CAVIN1 gene, which could affect energy and immune response. These changes are not explained by the well-established impact of tobacco on DNA methylation, which is commonly mixed with joints by most cannabis users.

Dr Emma Dempster, senior lecturer at the University of Exeter and first author of the study, said: “This is the first study to show that frequent use of high potency cannabis leaves a distinct molecular mark on DNA, particularly affecting energy-related genes. and immune function.

“Our results provide important insights into how cannabis use can alter biological processes. DNA methylation, which bridges the gap between genetics and environmental factors, is a key mechanism that allows external influences, such as substance use, to impact gene activity. These epigenetic changes, shaped by lifestyle and exposures, offer valuable insight into how cannabis use may influence mental health. by biological means.

Dr Emma Dempster meta-analyzed data from two cohorts: the GAP study, which includes patients with a first episode of psychosis in south London and the Maudsley NHS Foundation Trust, and the EU-GEI study, which includes patients with a first episode of psychosis and in good health. controls in England, France, the Netherlands, Italy, Spain and Brazil.

This totaled 239 participants with a first episode of psychosis and 443 healthy controls representing the general population of the two study sites and with DNA samples available.

Most cannabis users in the study used high-potency cannabis more than once a week (defined as frequent use) and had first used cannabis at the age of 16 on average.